Support inline-selection in entries (#318459)
	
	* gtk/gtkentry.c:
	* gtk/gtkentrycompletion.c:
	* gtk/gtkentrycompletion.h:
	* gtk/gtkentryprivate.h:

	When enabled cursor-match is emited when the cursor is on
	a possible completion on the list. The default implementation
	will replace the contents on the entry with the contents of
	the text column in the completion model.

	Review and improvements by Matthias Clasen.

svn path=/trunk/; revision=17660