Thank you for your interest in contributing to this package. Unfortunately, I do not plan to continue maintaining this package.
The original purpose of this package was to provide a way to get a PSR-0 and Composer friendly port of Michel Fortin's PHP Markdown library on Packagist. Michel was originally uninterested in Composer and did not want to make changes and said I was free to fork and maintain a special Composer package.
In January of 2013 (or around then) Michel finally joined the Composer bandwagon. More details can be found here. This means that the major reason this port existed (to be a Composer friendly port) effectively went away. This corresponded with the 1.3 release of PHP Markdown.
Additionally, other versions of PHP Markdown parsers have come into existence and are quite nice.
Please feel free to continue to use it as-is but if you are starting a new project I would recommend finding another library. If you have a project already depending on this package, I would recommend planning to migrate to something that is better maintained.
Thanks for your support and using this library over the years.