Twit 03 view pager and fragments

Creates a view pager and migrates all activities to fragments. Authentication Manager has been refactored into the authentication fragment, to prevent lots callbacks.

![authenticationmenu](https://cloud.githubusercontent.com/assets/3380092/3855378/e9be7c2a-1ee3-11e4-9897-3c9a07d58463.png)
![viewpager](https://cloud.githubusercontent.com/assets/3380092/3855384/f066ba2e-1ee3-11e4-8124-92af39a6d7b8.png)

I would go against the novoda convention and argue the case that this should be on the fragment, not the activity. It's causing an unnecessary back and forth for no real benefit. 

This is because the activity has been started for a result, which only the calling fragment needs to know about.