Readme / License / Contributing

hey @bhollis, In an effort to get some consistency to the various README.md styles, etc.. I've gone ahead and given middleman-syntax a refresh. I've made a couple assumptions which I would like to swing by you.

- I've added the middleman 'Donate' section, is that ok?
- I've assumed your going to MIT license this and looking at the commits that should start in 2012

Thanks!