Rename for Arduino conventions

Signed-off-by: Gerald Van Baren <gvb@unssw.com>
Do Proportional (PID) control

Previous approach was Integral(ish) control, not true proportional.

Signed-off-by: Gerald Van Baren <gvb@unssw.com>
Merge pull request #1 from gvb/master

Proportional (P of PID) control