rearranged sass and updated chosen styles

chosen looks miles better
did a mediocre job of updating readme to reflect

argus's zenaida branch and brambling's styles branch require this to be merged
ok so this is a little gross
![image](https://cloud.githubusercontent.com/assets/1051450/3261282/9a031848-f257-11e3-9614-1cfe5f08fe37.png)
![](https://cloud.githubusercontent.com/assets/1051450/3261144/d77fb41c-f255-11e3-992f-caa27351ecea.png)

But I'm not sure of a better way to keep it cohesive like it is in the original Chosen styles, while still keeping the matching shadow. Also ugh why isn't there a nice easy way to do box shadows on only three sides