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>
* add a method to check barcode code format
ensure that the code to print is compatible with the ESC/POS formats and
also automatically check this format before printing (barcode() method).
* rewrite test using pytest's parametrize functionality
* add test for the 'check' argument
* update authors list