Merge branch 'issue-149'
Merge remote-tracking branch 'upstream/master'
First shot on limiting the mapView with a bounding box (iOS)
Fixed jitter when panning on the bounding box border.
Implemented MapBoundingBox on Android.

Small refactoring to make bounding box more cross platform.
All access to MapCenter goes via it's setter to ensure the view stays within the bounding box when panning.
Merge pull request #155 from txsmith/boundingbox

Limit the MapView with a bounding box of geo coordinates