Do the blog thing on the Gaslight.co thing

# **Warning: Do not merge!**

Ok, here's the deal: tumblr is hard. Markdown is awesome. GitHub is awesome. Rails is awesome.

I took the things that were not fun and combined them with the things that are. I built a "blog engine" from the files in the gaslight/posts repo. There are still things that need to be fixed:

## Features
- [x] syntax highlighting
- [x] markdown parsing
- [x] fancy smart quotes
- [x] comments
- [x] post title
- [x] index view (recent posts)
- [x] show view (single post)
- [x] active class on blog nav
- [x] author name
- [x] posted on
- [x] tags
- [x] search
- [x] TESTS
- [x] RSS feed
- [x] posts by year/month/day
- [x] cache posts#show
- [x] canonical uris
- [x] slugs
- [ ] redirect using tumblr id
- [x] social things
- [ ] podcast things (@mitchlloyd)

## Bugs
- [ ] WTF EpicEditor: http://gaslight.dev/admin/posts/115/edit