Import measure ui

### Story
* https://www.pivotaltracker.com/story/show/67995626

### Notes
* I used a mockup from December as guidance
* Updated file picker
* Switches for measure type and calculation radio buttons
* Changes the rebuild patients toggle to a checkbox, and gives it a nice style
* Shows rebuild patients only when updating
* Decently responsive across all browsers

### Screenshots 
The old UI:
![old import measure UI](https://cloud.githubusercontent.com/assets/2136286/2989021/efc81bd8-dc5f-11e3-8b73-78013e4df81a.png)

The new:
![new import/edit measure UI 1](https://cloud.githubusercontent.com/assets/2136286/2989167/4a0a4dfe-dc61-11e3-9aa3-7d7a43870bdd.png)
![new import/edit measure UI 2](https://cloud.githubusercontent.com/assets/2136286/2989166/4a08fb0c-dc61-11e3-8ad7-14afb93cbf8f.png)
![new import/edit measure UI 3](https://cloud.githubusercontent.com/assets/2136286/2988995/b81a5322-dc5f-11e3-9b90-7529b2fffdb8.png)
![new import/edit measure UI 4](https://cloud.githubusercontent.com/assets/2136286/2989197/9cedbbd2-dc61-11e3-8298-ba8250848264.png)
![new import/edit measure UI 5](https://cloud.githubusercontent.com/assets/2136286/2988993/b81797ea-dc5f-11e3-838c-2d46e226858a.png)