2004-03-07  Sven Neumann  <sven@gimp.org>

	Made size of undo previews configurable. Not dynamic for now, but
	at least not hardcoded any longer. Fixes bug #119905:

	* app/config/gimpcoreconfig.[ch]
	* app/config/gimprc-blurbs.h: added "undo-preview-size" property.

	* app/core/gimpundo.[ch]: use the new property instead of a
	hardcoded value.

	* app/widgets/gimpundoeditor.[ch]: added a "preview-size"
	construct property.

	* app/gui/dialogs-constructors.c: changed accordingly.

	* app/gui/preferences-dialog.c: added a widget to control the undo
	preview size.