2002-12-18  Michael Natterer  <mitch@gimp.org>

	* app/tools/gimpcurvestool.c
	* app/tools/gimplevelstool.c: replaced lots of "gpointer data"
	parameters of local callbacks by GimpCurvesTool* and
	GimpLevelsTool* pointers. Makes the code shorter and more
	readable. Some random cleanup.

	* app/tools/gimphistogramtool.c: fixed type of "parent_class"
	pointer.