Add HomeActivity and TabBarActivity with stub fragments

HomeActivity hides title bar and GO button starts
  VIPTabBarActivity

VIPTabBarActivity uses a FragmentPagerAdapter and creates
  three dummy tabs. Also has "About" button on ActionBar

TODO:
  - Create Fragment classes for each actual tab
  - Move Fragment classes to separate files
Refactor Home/Ballot fragments to separate classes
Update README with dependencies
Merge pull request #1 from votinginfoproject/feature/app-architecture

Basic App Architecture