2009-01-20  Hans Breuer  <hans@breuer.org>

	* app/undo.[ch] app/commands.[ch] app/menus.c app/diagram.c 
	  data/*-ui. : implement "Objects/Move to layer above/below" 
	(maintaining connections between layers). Fixes bug #59105.
	* samples/undo-check.dia a diagram to play with the above

svn path=/trunk/; revision=4211