Made Nearby use UICollectionView.

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

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

Change-Id: I957a72b25205415318d809b4899dc33dd927bb8a