step/dir firmware for the polargraph kritzlerbot

I like the polargraph controller
http://polargraph.co.uk

but its current choice of electronics somewhat limits the choice and size of stepper motors one can use.

I went with stepstick drivers with 1/16 microstepping and modded the polargraph firmware to work with step/direction drivers.

Note: my printed files are here: http://www.thingiverse.com/thing:16692