2005-03-19  Michael Natterer  <mitch@gimp.org>

	* app/core/gimpimage-sample-points.c
	* app/display/gimpdisplayshell-draw.c
	* app/display/gimpdisplayshell.c
	* app/tools/gimpcolortool.c: make sure sample points always have
	coordinates in the range [0..width/height-1], also added lots of
	+0.5 because they live at the pixels' centers, not at their
	borders. Fixed drawing of sample points at the display borders.