* bus/driver.c (bus_driver_handle_introspect): Add signals

* bus/driver.c (bus_driver_handle_introspect): Add signals
  to the introspect data. (patch from Daniel P. Berrange
  <dan at berrange.com>)

* bus/dispatch.c (check_existent_ping): Add testcase for Ping

* dbus/dbus-connection.c (_dbus_connection_peer_filter,
  _dbus_connection_run_builtin_filters): Changed these to
  be unlock_no_update functions and call
  _dbus_connection_send_unlocked_no_update instead of
  dbus_connection_send to avoid locking errors.

* doc/TODO: Removed the make Ping test TODO