* libgimpwidgets/gimpsizeentry.[ch]: added function
	gimp_size_entry_show_unit_menu() for convenience.

	* app/tools/gimprectangleoptions.[ch]
	* app/tools/gimprectangletool.[ch]:  more work on
	controls in Tool Options.  Can now resize rectangle
	by dragging any corner or edge -- move rectangle by
	clicking inside and dragging.