Add map fragment and fix stuff
Summary:
Fix location following in the map
Use AsyncTask to load data
Fix map stuff and add comments
Fix database connection leak
Fix warning of unchecked operations
Test Plan: Check it builds and it doesn't crash
Reviewers: valerio.bozzolan
Reviewed By: valerio.bozzolan
Subscribers: valerio.bozzolan, Libre BusTO
Tags: Libre BusTO
Differential Revision: https://gitpull.it/D56