/**********************************************************************************************
 * C PID Library - Version 1.0.1
 * modified my Matthew Blythe <[email protected]> mjblythe.com/hacks
 * originally by Brett Beauregard <[email protected]> brettbeauregard.com
 *
 * This Library is licensed under a GPLv3 License
 **********************************************************************************************/

 - For an ultra-detailed explanation of why the code is the way it is, please visit: 
   http://brettbeauregard.com/blog/2011/04/improving-the-beginners-pid-introduction/
   
 - This code is also modified to remove the ability to be called at irregular intervals.
   I assume that most folks coding in raw C can set up a regular timer-based interrupt.