Bug 575006 – Add preferences for snapping

	* app/config/gimpdisplayconfig.[ch]
	* app/config/gimprc-blurbs.h
	* app/display/gimpdisplayshell.c: applied part of a patch from
	Akkana Peck. This adds gimprc properties for the default values
	used for snapping in new image windows. It also changes the
	default value for "Snap to Canvas Edges" to TRUE. Let's test 
this
	for a while...


svn path=/trunk/; revision=28151