- Commit history added to repo, as an easier way for people to see view
the changes over time.
- Grbl logo copyright license added. All rights reserved with regards
to the Grbl logo.
- G2/3 full circles would sometime not execute. The problem was due to
numerical round-off of a trig calculation. Added a machine epsilon
define to help detect and correct for this problem. Tested and should
not effect general operation of arcs.
