operations and their inner nodes.

	* docs/index-static.html.in:
	* gegl/gegl-node.c: (property_changed):
	* gegl/gegl-operation-meta.c: (gegl_operation_meta_init),
	(redirect_new), (redirect_free),
	(gegl_node_copy_property_property), (gegl_operation_meta_redirect),
	(gegl_operation_meta_property_changed):
	* gegl/gegl-operation-meta.h:
	* operations/meta/dropshadow.c: (associate), (class_init): Use the new
	meta op infrastructure.