Fri Oct  1 15:18:34 1999  Austin Donnelly  <and1000@research.att.com>

	* app/channel.h: don't want sub-undo type
	* app/gimpimage.c: undo_push_channel() takes ADD or REMOVE type
	* app/undo.c: undo_push_channel() takes type.  More specific
	    CHANNEL_{ADD,REMOVE}_UNDO types.
	* app/undo.h: undo_push_channel() prototype.
	* app/undo_types.h: More specific CHANNEL_{ADD,REMOVE}_UNDO types.