updates ui for download buttons

Closes #146 

Better presentation for download buttons/types

#### mit-us-ma-e25zcta5dct-2000
![screen shot 2014-11-20 at 2 45 56 pm](https://cloud.githubusercontent.com/assets/1656824/5134573/34bad34a-70c4-11e4-883c-5fdb9dfe182e.png)

#### stanford-jr127wd5810
![screen shot 2014-11-20 at 2 46 13 pm](https://cloud.githubusercontent.com/assets/1656824/5134576/42fdc66a-70c4-11e4-844b-cf7aade7170d.png)