added a way for sidebar views to specify small images that
	are displayed in their tab for notification purposes.  Used
	that to make the notes component indicate if a note is present or
	not.

	* components/notes/nautilus-notes.c: (get_bonobo_properties),
	(set_bonobo_properties), (load_note_text_from_metadata),
	(done_with_file), (notes_load_metainfo),
	(notify_listeners_if_changed), (notes_save_metainfo), (do_destroy),
	(notes_get_indicator_image), (make_notes_view):
	added a property bag to the notes component to provide a tab_image
	property, and made it notify the listeners when the note text
	changes.

	* icons/Makefile.am:
	* icons/note-indicator.png:
	new notes indicator image from Arlo.

	* src/nautilus-sidebar-tabs.c: (tab_item_destroy),
	(pixbuf_composite), (draw_one_tab_plain), (draw_one_tab_themed),
	(get_tab_width), (draw_or_layout_all_tabs),
	(nautilus_sidebar_tabs_expose),
	(nautilus_sidebar_tabs_update_tab_item), (get_tab_item_from_view),
	(nautilus_sidebar_tabs_update_all_indicators),
	(nautilus_sidebar_tabs_update_indicator),
	(tab_indicator_changed_callback),
	(nautilus_sidebar_tabs_connect_view):
	* src/nautilus-sidebar-tabs.h:
	made the sidebar tabs hook up to the nautilus_view's tab_image
	property and use it to display a notification image in the tab
	if necessary.

	* src/nautilus-sidebar.c: (view_loaded_callback),
	(nautilus_sidebar_add_panel):
	connect the sidebar tabs to a newly added view, once the view
	is loaded.

	* src/nautilus-view-frame.c: (nautilus_view_frame_get_control):
	* src/nautilus-view-frame.h:
	added nautilus_view_frame_get_control so view properties can be
	accessed by the sidebar.