2000-06-13  Jay Cox  <jaycox@gimp.org>

        These files should have been commited in my 2000-05-08 commit
	but somehow they didnt make it.

	* app/hue_saturation.c
	* app/levels.c
	* app/posterize.c
	* app/threshold.c: Add a call to image_map_clear in the
	preview toggle button callback.  This makes the preview toggle
	button behave as expected.

	* app/histogram_tool: remove an unnecessary include.