Add attribution: This repository copies significant portions of https://github.com/mike42/escpos-php

This repository, in its current form, infringes copyright.

The "Initial Implementation" contains code for generating print commands in EscPos.php and Printer.php:
* https://github.com/xiidea/php-esc-pos/commit/0827b5f54e8688a0c62761b5cbe6ecfefc1c2810

This is a copy of code which I wrote and published some 6 months earlier:
* https://github.com/mike42/escpos-php/blob/d7383a3fb5df173a5daa5e6b7030b58e1d4b5b8c/escpos.php

As this code has since been MIT-licensed, it would be fine for you to use it, provided that you correctly attribute it. I've created a pull request which will acknowledge the source and copyright status of the code, in order to comply with the licensing terms.

To fix this issue, please accept this pull request.