API. All code to do with positioning the stage has been removed so
the window is left where Windows wants to put it and it can not be
moved with clutter_actor_set_position.
* clutter/win32/clutter-stage-win32.h (ClutterStageWin32): Remove
win_xpos and win_ypos.
* clutter/win32/clutter-event-win32.c (message_translate): Remove
the handler for WM_MOVE because the stage no longer cares where it
is positioned.