Added a class to send ROI commands
Point camera at user on every location update
Add a enum to select the type of follow-me
Removed old method for follow-me preference
Implemented Circle Mode
Extract math related methods to the right class
prevents settings follow radius to a negative number
implemented spinner to select follow type
Removed the old fixed follow type
Renamed variable
Renamed package
Extracted follow algorithms to new class.
prevents entering follow me when disarmed or disconnected.
decrease size of follow type selection spinner.
Merge branch 'master' into follow_roi

Conflicts:
	Android/src/org/droidplanner/android/gcs/FollowMe.java
Merge pull request #871 from arthurbenemann/follow_roi

Follow ROI and follow-type selection