* bus/activation.c: (bus_pending_activation_entry_free),
	(bus_pending_activation_free), (bus_activation_new),
	(bus_activation_unref), (bus_activation_service_created),
	(bus_activation_activate_service):
	* bus/activation.h:
	* bus/bus.c: (bus_context_new):
	* bus/desktop-file.c: (new_section):
	* bus/driver.c: (bus_driver_send_service_deleted),
	(bus_driver_handle_activate_service):
	* bus/services.c: (bus_registry_new), (bus_registry_ensure):
	* bus/services.h:
	* dbus/dbus-connection.c:
	(dbus_connection_send_with_reply_and_block):
	* dbus/dbus-message.c: (dbus_message_append_args_valist):
	* dbus/dbus-protocol.h:
	Make activation work better. Now pending activations will be queued
	and the daemon won't try to activate services that are already registered.