homing: Create Homing class from gcode

Create the Homing class in the gcode handler instead of in the
kinematic classes.  This will make it easier to pass error messages
back to the user.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/delta.py

@@ -83,9 +83,9 @@ class DeltaKinematics:
                * self.steppers[i].step_dist
                for i in StepList]
         return self.actuator_to_cartesian(pos)
-    def home(self, toolhead, axes):
+    def home(self, homing_state):
         # All axes are homed simultaneously
-        homing_state = homing.Homing(toolhead, [0, 1, 2])
+        homing_state.set_axes([0, 1, 2])
         s = self.steppers[0] # Assume homing parameters same for all steppers
         self.limit_xy2 = self.max_xy2
         # Initial homing
@@ -101,7 +101,6 @@ class DeltaKinematics:
         coord[2] -= s.homing_retract_dist
         homing_state.plan_home(list(coord), homepos, self.steppers
                                , s.homing_speed/2.0)
-        return homing_state
     def motor_off(self, move_time):
         self.limit_xy2 = -1.
         for stepper in self.steppers: