Made Nearby use UICollectionView.

Change-Id: I8aa5a50aa21c26deba4b0de752a4e83668f749fa
Moved angle/distance calc into Nearby controller.

This will vastly simplify doing an 'immersive' presentation
of nearby results.

Also sped things up a bit by dealing with coordinates with
lighter weight struct rather than location object.

Change-Id: Ia69b94e983e6c1ecabd694ff9ce91f091138a40f