Adding Markdown to Ddoc

[Sönke Ludwig]

Am 06.12.2017 um 05:11 schrieb Walter Bright:
> https://help.github.com/articles/basic-writing-and-formatting-syntax/
> 
> Anyone interested in picking up the flag?
> 
> (I know this has come up before, and I've been opposed to it, but I've 
> changed my mind.)

This is great news! While I don't have the time to work on this 
directly, I can offer vibe.d's Markdown module* (re-licensing as 
necessary): 
https://github.com/vibe-d/vibe.d/blob/master/textfilter/vibe/textfilter/markdown.d

Markdown is a strange thing to parse in the classical way due to its 
original regex-cascade style of implementation/design, so it was kind of 
difficult to find representations that allow reasonably efficient and 
comprehensible processing.

* There is also "dmarkdown", which is just a fork of the vibe.d code