2006-04-02  Michael Natterer  <mitch@gimp.org>

	* app/core/gimpimage-undo-push.[ch]
	(gimp_image_undo_push_image,item_parasite): use "const GimpParasite*"
	insted of gpointer for the parasite parameter.

	* app/core/gimpparasitelist.[ch] (gimp_parasite_list_add): added
	const to the parasite parameter, return the actually added
	parasite (which is a copy).

	* app/core/gimpunit.[ch] (_gimp_unit_new): added const to all
	string parameters.