* gladeui/glade-property-class.[ch]: added glade_property_class_compare()
	
* gladeui/glade-editor-property.c: use new compare function in
  glade_editor_property_commit() instead of g_param_values_cmp()
  since GBoxed comparison is not well defined.
  Fixes bug #528511.

svn path=/trunk/; revision=1800