[Radiant] Markdown + Smarty Pants

[Sean Santry]

> Awesome. Bodhi, would you have a chance to look this over and apply  
> it?
>
> I looked at it briefly and it looked well implemented and tested.
> Delicious! :-)

Now that the standalone SmartyPants filter is in r114 I've patched  
the Markdown filter so it will educate quotes as well.

The patch against r114 (with updated tests) is in

	http://dev.radiantcms.org:9007/radiant/ticket/363

- Sean