* configure.ac: Bumping gtk+ required version to 2.14

	* gladeui/glade-xml-utils.c, gladeui/glade-widget-adaptor.[ch],
	gladeui/glade-property-class.[ch], gladeui/glade-project.c: Added support
	for "builder-since" versioning (since builder supported this property/widget).

	* plugins/gtk+/gtk+.xml.in: Marked appropriate properties and objects "builder-since"
	and brought up to date new properties and signals introduced in 2.14.

	* gladeui/glade-base-editor.c: Plugged resource leak in finalize().


svn path=/trunk/; revision=2060