Full text feed

Hello,

I made some adjustments to your RSS plugin. I added the full text of each article.
Also since the description field of RSS feed items should be text only, I simply removed the HMTL tags and wrapped it in CDATA tags, just to be sure.
As far as I can see it's a new behaviour of Jekyll 2.3.0: post.excerpt and post.content now return rendered text whereas it used to be the raw (e.g. markdown formatted) content of the post.
Feel free to pull the changes or simply ignore my message if you don't like them.

Greetings
ron