WLBL builder with measure dropdown scroll

### Story ###
- https://www.pivotaltracker.com/story/show/66685304

### Notes ###
- added custom ```.scrollable-menu``` class for bootstrap dropdown menu [(source)](http://stackoverflow.com/a/19229738)
- added popovers for condensed list items

### Screenshot ###
![screen shot 2014-08-20 at 4 05 37 pm](https://cloud.githubusercontent.com/assets/456952/3987409/9ac9151e-28a5-11e4-8b8d-8f4de3a7379f.png)