Add sliding menu library
Basic sliding menu working on messages
Add drawer to all activities
Add icons to menu items
Set menu onclick to change activities
Change action bar text on drawer open/close
Refactor menu helper
Remove menu activity and fix backstack
Rename MessagesActivity to InboxActivity
Fix signup backstack problems.

Signup is now an activity launched for result that returns to login.
This makes it so we only have to handle one entry point into the app
Merge pull request #58 from Lyricoo/slider

Basic Menu Slider
Merge pull request #62 from Lyricoo/inbox

Inbox