and use SetWindowPos instead for one of the MoveWindow()s
- call STATUSBAR_GetInfoPtr *once* like Windows does, not twice (used to be
  in every sub function, too)
- remember hwndParent from create struct to use in at least WM_CREATE and
  WM_SIZE instead of GetParent() like in Windows
- added DefWindowProc call to WM_SIZE like in Windows
- added InvalidateRect, UpdateWindow to WM_CREATE like in Windows
- much more verbose +statusbar output
- rename part_num to nPart for consistency
- added nclm.cbSize to SystemParametersInfoA call
- added FIXME to STATUSBAR_SetParts