Processes the Markdown language with the bundled discount library.

Markdown is a lightweight markup language created by John Gruber. It is also
the name of the original tool written in Perl that converts such markup into
HTML.

This library is a wrapper for a modified version of the discount Markdown
processor, created by David Parsons. It supports several extensions of the
original Markdown language, including smartypants-style substitutions, pandoc-
style document headers, and parts of Markdown Extra.

The modifications to discount include discarding several parts important only
to stand-alone applications that accompany the library code, better consistency
in library interface functions, thread-safety without eager initialization of
globals, usage of the Zend memory manager and support for Microsoft Windows.

Discount is available at <http://www.pell.portland.or.us/~orc/Code/discount/>.

The page of the original Markdown is available at
<http://daringfireball.net/projects/markdown/>.