Allow to inspect P/I/D terms before output

[egueli]

This PR adds three methods to inspect what are the individual contributions to the output. This allows to know more about how the controller is operating.

Also fixes some whitespace issues.

[oakwhiz]

Inserting the following code snippet seems to work for me so far on the latest revision:

      lastPTerm = kp * ( pOnE ? error : dInput);
      lastITerm = outputSum;
      lastDTerm = -kd * dInput;