Lock MainActivity to portrait-only.
Use fragment's containers in Activity and fix transition logic.

If MainActivity, LegislatorListFragment, and SearchFragment
are all controllers, they each control their Views.
MainActivity wasn't adhering to this pattern, which
led to a ton of issues when try to do more interesting things
with each controller's StateManager.
If user has stored legislators, show them when app opened.

Also, added an actionbar item to clear data on demand.
Change up EditText focus.