Structure and style the Add Tool view.

:fork_and_knife: 

This styles the Add Tool view to look like the mockup (https://projects.invisionapp.com/share/9U11E3OGT#/screens).

It looks like: 
![screen shot 2014-07-16 at 2 33 59 pm](https://cloud.githubusercontent.com/assets/928367/3603567/1aaef644-0d18-11e4-954f-5973973db5e8.png)