2001-05-06  Michael Natterer  <mitch@gimp.org>

	* app/appenums.h: added GimpDropMode...
	* app/gimpdnd.h: ...removed from here.

	* app/gimpimage.[ch]:
	- New signal "mode_changed".
	- removed "const GimpImage*" from gimp_image_colormap_changed()
	  because a signal emission is never "const" for the object
	  which emits the signal.
	- Fixed gimp_image_[set|get]_component_[active|visible]():
	  ALPHA_CHANNEL maps to ALPHA_PIX only in RGB mode, use
	  ALPHA_G_PIX/ALPHA_I_PIX in GRAY/INDEXED mode.

	* app/gimpimage-convert.c
	* app/undo.c: call gimp_image_mode_changed().

	* app/gimpviewable.c: added an implementation of
	"invalidate_preview" which frees the preview temp_buf which may be
	attached to the viewable. Subclasses need to chain up now.

	* app/gimpdrawable.c
	* app/gimpimage.c: chain up in invalidate_preview().

	* app/widgets/gimpchannellistview.c: connect to the image's
	"mode_changed" signal and rebuild the channel list in the
	callback.

	* app/widgets/gimpcontainerview.h: indentation.

	* app/widgets/gimpdockbook.c: set the dockable's context to NULL
	in gimp_dockbook_remove()

	* app/widgets/gimpimagedock.c: forgot to actually set the dock's
	image in gimp_image_dock_new().

	* app/gui/dialogs-constructors.c: added a get_name_func() for tool
	views which returns the tool's "blurb". It's safe to assume now
	that a dockable's context will exist as long as the dockable
	exists unless it's explicitely set to NULL, so remove ugly hacks
	handling context destruction.

	* app/tools/gimptool.c: removed COMPAT_CRUFT and useless #include's.