* gladeui/glade-signal.c: Added "swapped" attribute and read/write from xml, swapped attribute is
	always saved, if its missing on load and user_data (object) is set, we assume a swapped default.

	* gladeui/glade-signal-editor.c: Allow toggling "swapped" flag of a signal if user data is set.

	* gladeui/glade-widget.c: Account for new signal "swapped" flag when modifying local signals.