Prettied up readme's for charms

[Kapil Thangavelu]

Excerpts from Jorge O. Castro's message of Wed Jan 25 21:22:49 -0500 2012:
> We use READMEs in the Charm browser so that charms have their own
> "homepage". Today I ran into this:
> 
> http://documentup.com/#
> 
> and thought I'd point it out as a pretty slick addition we should consider.
> 

This doesn't quite look right for functionality. In that its tied to github and 
a third party server and only supports a single format, as opposed to just a 
multi-format rendering solution.

right now the formatting problem is that we lack much by way of knowledge wrt 
to what format the documentation is. It would be helpful if people could utilize the 
appropriate extension (.md, .rst, etc) when adding readme's to charms.

The github markup tools are available, and are probably the best way to do a 
rendering integration, being used in production, and supporting a wide variety 
of syntaxes.

https://github.com/github/markup


cheers,

Kapil