Refactor PID Class

[pknessness]

I have found a guide on making a more robust and expansive PID Class.
http://brettbeauregard.com/blog/2011/04/improving-the-beginners-pid-introduction/

This is it

The job is to improve our PID class with the guidelines in this guide, and understand why each change is being made.
This is something of a complex task.

Other things to look into are reset tiebacks, integer math, different pid forms, and using velocity instead of position (all listed at the end of the guide, and while I do not know what these are, they should be looked into to make our PID class the best it can be. There is a fairly good chance these are also all useless)

You may also want to look at taproot's PID class (UW's code)
https://github.com/uw-advanced-robotics/taproot/blob/develop/src/tap/algorithms/smooth_pid.cpp