2004-09-03  Sven Neumann  <sven@gimp.org>

	* libgimpbase/gimpchecks.h
	* libgimpbase/gimplimits.h: moved check size and check color
	defines. It makes a lot more sense to keep them in gimpchecks.h.

	* libgimpbase/gimpchecks.c (gimp_checks_get_shades): documented.

	* libgimp/gimpdrawablepreview.c (gimp_drawable_preview_draw):
	added a sanity check so we don't crash if the drawable pointer
	should ever be NULL here.