* 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
The changes done in this commit should help with the open issues:
#5, #27 and #161.
The old implementation lacked the NUL char at the end of the command, as
defined on the Epson ESC/POS Reference Guide (see
https://reference.epson-biz.com/modules/ref_escpos/index.php?content_id=53
). Also, the horizontal tab control character (CTL_HT) shouldn't be
there.
This implementation allows setting up to 32 tabs with a given tab width.
Both values are checked to be in the valid ranges defined on the guide.
Also, the TabPosError exception text has been rewritten to define the
stated above.
Lucy Linder