WaypointHolder methods to remove and swap waypoints
 - to support table view editing
Basic tableview based waypoint editing

- remove/reorder only

Make mapview more prominent in editing mode
Waypoint map display functionality moved to WaypointBaseMapController

- quick way to allow reuse of existing map-waypoint display
functionality
- GCSMapViewController and WaypointViewController now subclasses of
this class

Update WaypointViewController's map view on removal/reordering of
waypoints in the table view