Avoid recreating pangolayouts in GtkTextView on cursor movement (#435405,

Avoid recreating pangolayouts in GtkTextView on cursor movement (#435405,

2007-06-01  Yevgen Muntyan  <muntyan@tamu.edu>

	Avoid recreating pangolayouts in GtkTextView on cursor movement
	(#435405, Behdad Esfahbod).

	* gtk/gtktextlayout.c:
	* gtk/gtktextlayout.h: new GtkTextLayout method invalidate_cursors(),
	and functions gtk_text_layout_invalidate_cursors() and
	gtk_text_layout_cursors_changed(), to use when invalidation is due
	to moved marks or changed selection.

	* gtk/gtktextbtree.c:
	* gtk/gtktextbtree.h: use what's appropriate when invalidating layout.

	* gtk/gtk.symbols: add new functions.

	* README.in: added a note about changed GtkTextLayout API.

svn path=/trunk/; revision=18000