kinematics: Add a "none" debugging kinematics

Add a dummy kinematics class for development testing.

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

klippy/kinematics/none.py

@@ -0,0 +1,26 @@
+# Dummy "none" kinematics support (for developer testing)
+#
+# Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+class NoneKinematics:
+    def __init__(self, toolhead, config):
+        pass
+    def get_steppers(self, flags=""):
+        return []
+    def calc_position(self):
+        return [0, 0, 0]
+    def set_position(self, newpos, homing_axes):
+        pass
+    def home(self, homing_state):
+        pass
+    def motor_off(self, print_time):
+        pass
+    def check_move(self, move):
+        pass
+    def move(self, print_time, move):
+        pass
+
+def load_kinematics(toolhead, config):
+    return NoneKinematics(toolhead, config)