added a partial release option to "m84" aka "stepper release". If you do tiny layers, you might want to keep the z-axis powered to not loose height positioning after homeing.
- The temperature control is pretty much complete
(not sure what to do w/ autotemp though)
Changed the pins assignment to clearly separate bed and extruder heaters
and temp sensors, changed a bit how termistor tables are handled.
- The steppers control is rudimentary
(only chanages what pins it uses depending on the active_extruder var,
but that's enough for switching extruder in the start.gcode in the
the profiles)
- Tested only w/ RAMPS 1.4