2003-10-24  Sven Neumann  <sven@gimp.org>

	* app/tools/Makefile.am
	* app/tools/gimphistogramoptions.[ch]: new tool options class
	GimpHistogramOptions, derived from GimpColorOptions.

	* app/tools/gimpcoloroptions.c (gimp_color_options_gui): add
	gimp_histogram_options_gui() when called with GimpHistogramOptions.
	This a bit weird since the class hierarchy is the other way around
	but it makes things easier.

	* app/tools/gimphistogramtool.c
	* app/tools/gimplevelstool.c
	* app/tools/gimpthresholdtool.c: use GimpHistogramOptions and
	connect the histogram views to the "histogram-scale" property.
	Perhaps not perfect GUI-wise but it let's you choose the histogram
	scale and stores this setting per tool. Fixes bug #125306.

	* app/widgets/gimphistogramview.c: prefixed property names with
	"histogram-" so they match the GimpHistogramOptions property.

	* app/widgets/gimphistogrambox.c: minor cleanup.