Replaces PololuQik motor code with Dagu controller specific code

This is completely untested right now, since I don't have access
to a Dagu board.
Updates the python code to switch to the Dagu motor controller style

The motor controller is now transparent to the code, since it
allows the arduino to control each motor individually. In order to
control motors, you simply need to create the Motor classes from
user code.

This is also completely untested right now.
Adds digital/analog output, fixes servos

This is a rather large commit. It includes:
- Adding support for digital and analog outputs, in addition to
  the existing support for digital and analog inputs. This required
  renaming some classes, and arrays.
- Fixes the servo output, to allow negative angles, and scale the
  received value to [-180, 180] correctly on the Arduino side.
- Removes example code from the arduino.py file. This will be moved
  to the examples folder soon.
Adds examples for servos, digital output, and IR (analog input)