gcode: Move definition of CommandError and Coord from homing.py to gcode.py

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

klippy/gcode.py

@@ -1,13 +1,17 @@
 # Parse gcode commands
 #
-# Copyright (C) 2016-2020  Kevin O'Connor <kevin@koconnor.net>
+# Copyright (C) 2016-2021  Kevin O'Connor <kevin@koconnor.net>
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
 import os, re, logging, collections, shlex
-import homing
+
+class CommandError(Exception):
+    pass
+
+Coord = collections.namedtuple('Coord', ('x', 'y', 'z', 'e'))
 
 class GCodeCommand:
-    error = homing.CommandError
+    error = CommandError
     def __init__(self, gcode, command, commandline, params, need_ack):
         self._command = command
         self._commandline = commandline
@@ -68,7 +72,8 @@ class GCodeCommand:
 
 # Parse and dispatch G-Code commands
 class GCodeDispatch:
-    error = homing.CommandError
+    error = CommandError
+    Coord = Coord
     def __init__(self, printer):
         self.printer = printer
         self.is_fileinput = not not printer.get_start_args().get("debuginput")