Switch to Android 5.0 / Material theme

This uses the appcompat library, which requires we move some of our code
over to the support library. This is a good long-term decision anyways,
as it should allow us to easily support older android devices in the
future, if we choose.
Switch to a ViewPager for tabs

In Android 5.0 and the associated support libraries, ActionBar
navigation is deprecated. This keeps us from styling the elements
properly.

We gain the ability to swipe between views (except when swiping over a
map).

However, we lose the nice compact view created on tablets and on
landscape mode where the tabs were merged into the title bar. I've got
a few ideas on how to mitigate this.
Merge pull request #13 from routemaster/material

Switch to the New Android 5.0 Material Theme