SETUP move code to src

This way we can ensure that the packaged code is tested.
See https://hynek.me/articles/testing-packaging/ or c62a78c015

+ DOC adapt doc to new structure and test doc with travis

src/escpos/config.py

@@ -0,0 +1,118 @@
+""" ESC/POS configuration manager.
+
+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
+import yaml
+
+from . import printer
+from . import exceptions
+
+
+class Config(object):
+    """  Configuration handler class.
+
+    This class loads configuration from a default or specificed directory. It
+    can create your defined printer and return it to you.
+    """
+    _app_name = 'python-escpos'
+    _config_file = 'config.yaml'
+
+    def __init__(self):
+        """ Initialize configuration.
+
+        Remember to add anything that needs to be reset between configurations
+        to self._reset_config
+        """
+        self._has_loaded = False
+        self._printer = None
+
+        self._printer_name = None
+        self._printer_config = None
+
+    def _reset_config(self):
+        """ Clear the loaded configuration.
+
+        If we are loading a changed config, we don't want to have leftover
+        data.
+        """
+        self._has_loaded = False
+        self._printer = None
+
+        self._printer_name = None
+        self._printer_config = None
+
+    def load(self, config_path=None):
+        """ Load and parse the configuration file using pyyaml
+
+        :param config_path: An optional file path, file handle, or byte string
+            for the configuration file.
+
+        """
+
+        self._reset_config()
+
+        if not config_path:
+            config_path = os.path.join(
+                appdirs.user_config_dir(self._app_name),
+                self._config_file
+            )
+
+        try:
+            # First check if it's file like. If it is, pyyaml can load it.
+            # I'm checking type instead of catching exceptions to keep the
+            # exception handling simple
+            if hasattr(config_path, 'read'):
+                config = yaml.safe_load(config_path)
+            else:
+                # If it isn't, it's a path. We have to open it first, otherwise
+                # pyyaml will try to read it as yaml
+                with open(config_path, 'rb') as config_file:
+                    config = yaml.safe_load(config_file)
+        except EnvironmentError:
+            raise exceptions.ConfigNotFoundError('Couldn\'t read config at {config_path}'.format(
+                config_path=str(config_path),
+            ))
+        except yaml.YAMLError:
+            raise exceptions.ConfigSyntaxError('Error parsing YAML')
+
+        if 'printer' in config:
+            self._printer_config = config['printer']
+            self._printer_name = self._printer_config.pop('type').title()
+
+            if not self._printer_name or not hasattr(printer, self._printer_name):
+                raise exceptions.ConfigSyntaxError(
+                    'Printer type "{printer_name}" is invalid'.format(
+                        printer_name=self._printer_name,
+                    )
+                )
+
+        self._has_loaded = True
+
+    def printer(self):
+        """ Returns a printer that was defined in the config, or throws an
+        exception.
+
+        This method loads the default config if one hasn't beeen already loaded.
+
+        """
+        if not self._has_loaded:
+            self.load()
+
+        if not self._printer_name:
+            raise exceptions.ConfigSectionMissingError('printer')
+
+        if not self._printer:
+            # We could catch init errors and make them a ConfigSyntaxError,
+            # but I'll just let them pass
+            self._printer = getattr(printer, self._printer_name)(**self._printer_config)
+
+        return self._printer