Don't add pixbuf mime types if pixbuf backend is disabled.

Don't add pixbuf mime types if pixbuf backend is disabled.

	* backend/ev-document-factory.c: (gdk_pixbuf_mime_type_list),
	(mime_type_supported_by_gdk_pixbuf),
	(ev_document_factory_get_mime_types),
	(ev_document_factory_get_all_mime_types):

	Don't add pixbuf mime types if pixbuf backend is disabled.

	* shell/ev-application.c: (ev_application_get_uri_window):

	Fix for the bug 325815 - unhandled MIME type message doesn't
	appear a second time.

	* shell/ev-document-types.c: (ev_document_types_add_filters):
	* shell/ev-window.c: (page_changed_cb), (ev_window_setup_document),
	(password_dialog_response), (ev_window_popup_password_dialog),
	(ev_window_load_job_cb), (ev_window_sidebar_position_change_cb),
	(ev_window_run_fullscreen), (ev_window_stop_fullscreen),
	(ev_window_run_presentation), (ev_window_stop_presentation),
	(save_sizing_mode), (ev_window_zoom_changed_cb),
	(ev_window_continuous_changed_cb), (ev_window_rotation_changed_cb),
	(ev_window_dual_mode_changed_cb),
	(ev_window_sidebar_current_page_changed_cb),
	(ev_window_sidebar_visibility_changed_cb), (ev_window_dispose),
	(window_state_event_cb), (window_configure_event_cb):

	Cleanup additional uris holded by EvWindow.