Removed 'break' in one of if branches.

The 'break' caused unintended escaping from the for loop in
AvoidObstacle mode (found by Gareth and Augustine).
Cleaned up the code and added mode selection.
Updated touchbar conditions in avoid obstacle mode.
Lots of bug fixes and a new ADC function.

* Still updating motor speed control.
* Added one ADC utility function.
12/03/13 Changes