Attempt to fix distance and score calculations
Update the Tracker model so it saves itself
Store Coordinates objects instead of Position

A Position just has coords and timestamp attributes, and we're not using the
timestamp anyway. A Coordinate has latitude, longitude, and accuracy
attributes like the server expects.
Fix regression with distance and efficiency calc
Update Map view as GPS data changes

The HUD was updating, but the map wasn't.
Minor code formatting tweaks, round "distance"
Merge pull request #43 from routemaster/issues/update-map

Update Map view as GPS data changes
Merge pull request #46 from routemaster/features/submit-route

Features/submit route