CAM: store tool quantities in user units, not metric

src/Mod/CAM/Path/Tool/toolbit/util.py

@@ -25,7 +25,7 @@ import FreeCAD
 def to_json(value):
     """Convert a value to JSON format."""
     if isinstance(value, FreeCAD.Units.Quantity):
-        return str(value)
+        return value.UserString
     return value