2006-08-29  Michael Natterer  <mitch@gimp.org>

	Changed GimpViewable preview rendering to have a context to get
	FG/BG/whatever from. Use the context to enable dynamic FG/BG
	colors in gradients. Fixes bug #127676 and bug #352214. Addresses
	bug #128367 (doesn't fix it because there's no loading/saving and
	no GUI yet).

	* app/core/core-enums.[ch]: added enum GimpGradientColor to enable
	specifying gradient colors in terms of foreground and background.

	* app/core/gimpgradient.[ch]: added color_type members to the
	GimpGradientSegment struct and honor them in
	gimp_gradient_get_color_at(). Added GimpContext parameters to all
	functions which finally call get_color_at().

	* app/core/gimp-gradients.c: use the new method to implement the
	builtin gradients.

	* app/core/gimpviewable.[ch]: added GimpContext parameters to all
	get_preview() and get_pixbuf() functions.

	* app/core/gimpbrush.c
	* app/core/gimpbuffer.c
	* app/core/gimpdrawable-p...