Fixing issue with extra RPM steps on 0 step extruder moves, as per:  https://groups.google.com/forum/?fromgroups=\#\!topic/jetty-firmware/6N8qgSsq7-I
Merge pull request #30 from jetty840/dnewman-merge

Fixing issue with extra RPM steps on 0 step extruder moves, as per:  htt...