drop Python 2.7 support

Python 2.7 EOL is arriving on 2020-01-01: https://pythonclock.org/

This will allow us to use Python 3 only libraries, like python-barcode,
which can maintain a reduced, simpler codebase, due to only one version
to support.

Closes #371.

Signed-off-by: Romain Porte <microjoe@microjoe.org>

CONTRIBUTING.rst

@@ -27,25 +27,6 @@ Style-Guide
 
 When writing code please try to stick to these rules.
 
-Python 2 and 3
-^^^^^^^^^^^^^^
-We have rewritten the code in order to maintain compatibility with both Python 2 and Python 3.
-In order to ensure that we do not miss any accidental degradation, please add these imports to the top
-of every file of code:
-
-.. code-block:: Python
-
-  from __future__ import absolute_import
-  from __future__ import division
-  from __future__ import print_function
-  from __future__ import unicode_literals
-
-Furthermore please be aware of the differences between Python 2 and 3. For
-example `this guide <https://docs.python.org/3/howto/pyporting.html>`_ is helpful.
-Special care has to be taken when dealing with strings and byte-strings. Please note
-that the :py:meth:`~escpos.escpos.Escpos._raw`-method only accepts byte-strings.
-Often you can achieve compatibility quite easily with a tool from the `six`-package.
-
 PEP8
 ^^^^
 The entire codebase adheres to the rules of PEP8.

doc/user/usage.rst

@@ -84,7 +84,7 @@ to.
 ::
 
     p = printer.Serial("/dev/tty0")
-    
+
     # on a Windows OS serial devices are typically accessible as COM
     p = printer.Serial("COM1")
 
@@ -194,8 +194,8 @@ An USB-printer could be defined by::
 
 Printing text right
 -------------------
-Python-escpos is designed to accept unicode. So make sure that you use ``u'strings'`` or import ``unicode_literals``
+
-from ``__future__`` if you are on Python 2. On Python 3 you should be fine.
+Python-escpos is designed to accept unicode.
 
 For normal usage you can simply pass your text to the printers ``text()``-function. It will automatically guess
 the right codepage and then send the encoded data to the printer. If this feature does not work, please try to

examples/codepage_tables.py

@@ -1,7 +1,6 @@
 """Prints code page tables.
 """
 
-from __future__ import print_function
 
 import six
 import sys

examples/weather.py

@@ -13,7 +13,6 @@
 # Check out his github: https://github.com/AdamWhitcroft/climacons
 
 
-from __future__ import print_function
 from datetime import datetime
 import calendar
 import urllib

setup.cfg

@@ -63,10 +63,6 @@ tests_require =
 verbosity=3
 with-doctest=1
 
-[bdist_wheel]
-# This flag says that the code is written to work on both Python 2 and Python 3.
-universal=1
-
 [flake8]
 exclude = .git,.tox,.github,.eggs,__pycache__,doc/conf.py,build,dist,capabilities-data,test,src/escpos/constants.py
 max-line-length = 120

setup.py

@@ -22,10 +22,6 @@ setuptools_scm_template = """\
 # coding: utf-8
 # file generated by setuptools_scm
 # don't change, don't track in version control
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 version = '{version}'
 """

src/escpos/__init__.py

@@ -2,10 +2,6 @@
 """
 python-escpos enables you to manipulate escpos-printers
 """
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 __all__ = ["constants", "escpos", "exceptions", "printer"]
 

src/escpos/cli.py

@@ -9,10 +9,6 @@ It requires you to have a configuration file. See documentation for details.
 
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import argparse
 try:

src/escpos/config.py

@@ -4,10 +4,6 @@ This module contains the implentations of abstract base class :py:class:`Config`
 
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import os
 import appdirs

src/escpos/constants.py

@@ -11,10 +11,6 @@ moved to `capabilities` as in `escpos-php by @mike42 <https://github.com/mike42/
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import six
 

src/escpos/escpos.py

@@ -10,10 +10,6 @@ This module contains the abstract base class :py:class:`Escpos`.
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import qrcode
 import textwrap

src/escpos/exceptions.py

@@ -25,11 +25,6 @@ Result/Exit codes:
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
 
 class Error(Exception):
     """ Base class for ESC/POS errors """

src/escpos/image.py

@@ -8,10 +8,6 @@ This module contains the image format handler :py:class:`EscposImage`.
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import math
 from PIL import Image, ImageOps

src/escpos/katakana.py

@@ -4,11 +4,6 @@
 I doubt that this currently works correctly.
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
 
 try:
     import jaconv

src/escpos/magicencode.py

@@ -12,10 +12,6 @@ The code is based on the encoding-code in py-xml-escpos by @fvdsn.
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 from builtins import bytes
 from .constants import CODEPAGE_CHANGE

src/escpos/printer.py

@@ -8,7 +8,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import, division, print_function, unicode_literals
 
 import serial
 import socket

test/test_abstract_base_class.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 from nose.tools import raises
 

test/test_cli.py

@@ -2,10 +2,6 @@
 
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import os
 import sys

test/test_function_barcode.py

@@ -1,8 +1,4 @@
 #!/usr/bin/python
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 from escpos.constants import BARCODE_TYPE_A, BARCODE_TYPE_B

test/test_function_cashdraw.py

@@ -1,8 +1,4 @@
 #!/usr/bin/python
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 from escpos.exceptions import CashDrawerError

test/test_function_check_barcode.py

@@ -1,10 +1,6 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 import pytest

test/test_function_cut.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import six
 

test/test_function_image.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import pytest
 

test/test_function_linedisplay.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 

test/test_function_panel_button.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 

test/test_function_qr_native.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 from nose.tools import raises
 import pytest

test/test_function_qr_non-native.py

@@ -8,10 +8,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import pytest
 import mock

test/test_function_set.py

@@ -1,7 +1,3 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import six
 

test/test_function_softbarcode.py

@@ -1,8 +1,4 @@
 #!/usr/bin/python
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 import pytest

test/test_function_text.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import pytest
 import mock

test/test_load_module.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 

test/test_magicencode.py

@@ -8,10 +8,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import pytest
 from nose.tools import raises, assert_raises

test/test_printer_file.py

@@ -8,10 +8,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import six
 

test/test_raise_arbitrary_error.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import pytest
 import escpos

test/test_with_statement.py

@@ -7,10 +7,6 @@
 :license: MIT
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
 
 import escpos.printer as printer
 import escpos.escpos as escpos