* libnautilus/ntl-view-frame.c, libnautilus/ntl-view-frame.h:
	Changed NautilusViewFrame to allow creation of `Nautilus::View'
	objects that have additional interfaces while sharing the actual
	control. This will allow, for instance, the creation of components
	that are both a `Nautilus::View' and a `Bonobo::Embeddable'. The
	basic changes are to require a `BonoboObject' with a
	`Bonobo::Control' interface at construction time.
	- Two creation functions are provided: `nautilus_view_frame_new',
	which takes a GtkWidget, creates a new control that contains that
	widget, and the constructs a NautilusViewFrame with that control,
	and `nautilus_view_frame_new_from_control', which creates a
	NautilusViewFrame that gets added as an additional interface to an
	existing control.
	- In the course of doing this it became clear that it would be
	easier if NautilusViewFrame were changed to inherit from
	BonoboObject rather than GtkBin, so this was done; as a result,
	the nautilus_view_frame_get_bonobo_object call was removed, since
	the view_frame _is_ a bonobo object. However, a
	nautilus_view_frame_get_bonobo_control call was added as a
	convenience, to allow other code to avoid having to
	query_local_interface for the control object manually.
	* libnautilus/ntl-meta-view-frame.c,
	libnautilus/ntl-meta-view-frame.h,
	libnautilus/ntl-content-view-frame.c,
	libnautilus/ntl-content-view-frame.h: Analogous changes; mainly,
	added `nautilus_meta_view_frame_new',
	`nautilus_meta_view_frame_new_from_control',
	`nautilus_content_view_frame_new' and
	`nautilus_content_view_frame_new_from_control'.
	* components/help/hyperbola-nav-index.c,
	components/help/hyperbola-nav-tree.c,
	components/history/ntl-history-view.c,
	components/html/ntl-web-browser.c, components/notes/ntl-notes.c,
	components/websearch/ntl-web-search.c, src/ntl-app.c,
	src/file-manager/fm-directory-view.c: Fixed initialization and
	object creation functions to deal with the above API change.