Make tabs switch between different fragments

- Construct record and history Fragments.
- Create a tab listener that attaches and detaches the tab fragments.
- Dynamically add a MapFragment to record. You cannot do this
  statically, as child fragment support in Android sucks at the moment.
- Apply some configuration to the map.
- Save map state between "configuration changes" (eg. device rotation).
Two-space indent? And I'd prefer no blank line unless you had a particular reason for it.