2004-12-16  Michael Natterer  <mitch@gimp.org>

	* app/actions/actions.c (action_data_get_*): get gimp, display or
	image from a context only if it isn't NULL. Fixes warnings and
	crashes when dragging around some dockables (the dockables'
	context temporarily becomes NULL while dragging).

	Reordered checks for the passed "data" to be consistent across the
	various functions.

	Removed assertions which said "#warning: remove me before 2.2"