Changed stepper to always step in step_sweep
Also added whole/half step as a separate setting, with a singlestep_do_step function. Also added stepper to main.cpp.
Some changes to the stepper library
A few bug fixes, and changed various values to use ms instead of us dueto integer overflow problems.
wrote code for the stepper motor. Requires that the caller calls init withthe time that the function returned by the init function will be called.then the user must call this function at the given constant time intervalthis allows for sweep to work.Library also allows for independent control of the stepper.