Separate the AngularJs App controllers.

#327 
* Created a new controller called "Activity". (This will eliminate any unnecessary calls to activity-stream)
* Created a broadcast that communicates between the 2 controllers.
* Fixed the scroll when creating a new activity.
* Optimized the code in the main controller, Because we need to call it in many places, this will make it faster to load.

Adding new activity with the new fixes:
![activity](https://cloud.githubusercontent.com/assets/7369740/5554384/dc170fda-8c5a-11e4-8bd2-d1b2fc37d99d.gif)