Double Precision X GT2, Printrbot Simple

I have combined the extended X upgrade and the Double precision upgrade previously only available for the MXL belt. I will apologize in advance for the poor documentation, I am simply out of time.

I have been running this on my machine since early May, 2014 and all is well. I have also converted my printer to run 1/4 microsteps instead of 1/16 microsteps. See the MXL double precision for speed limits on the stock 1/16 microsteping.

http://www.printrbottalk.com/ is a fantastic resource f