Merge pull request #16 from vpython/compound_origin_fix

compound origin fix

Author: mwcraig

vpython/vpython.py

@@ -3144,6 +3144,7 @@ def handle_event(self, evt):  ## events and scene info updates
                 # Set attribute_vector.value, which avoids nullifying the
                 # on_change functions that detect changes in e.g. obj.pos.y
                 obj._pos.value = list_to_vec(p)
+                obj._origin = obj._pos
                 s = evt['size']
                 obj._size.value = obj._size0 = list_to_vec(s)
                 obj._axis.value = obj._size._x*norm(obj._axis)