moved the zero length move/pivot error checking and callback incrementing into...

moved the zero length move/pivot error checking and callback incrementing into the primitive functions themselves, instead of the dgoto method.

gorobot has been messing up anytime a goto command sequence results in a zero length pivot. (Which means the robot will fuckup and act stupid any time you try to get it to move in a straight line!)

Things would be much easier if the Garcia could simply execute zero length commands without barfing.