Service code cleanup

This pull request contains major code refactoring. The service class was too big and unweidly, so it has been split up into 4 components:

- AccelerometerMonitor
- LocationTracker
- RilExecutor
- CellTracker

The core of the app's detection features are now in CellTracker, which makes it easier to work with. Functionality should still be the same as before, the only code change was to add a movement monitor to the GPS (i.e. LocationTracker), previously only applied to accelerometer. Briefly tested and appears to be working as before.