added a finished signal to StreamPlayer, closes #2249

scene/audio/stream_player.cpp

@@ -170,6 +170,7 @@ void StreamPlayer::stop() {
 	stop_request=false;
 	playback->stop();
 	resampler.flush();
+	emit_signal("finished");
 
 	//set_idle_process(false);
 }
@@ -378,6 +379,8 @@ void StreamPlayer::_bind_methods() {
 	ADD_PROPERTY( PropertyInfo(Variant::BOOL, "stream/paused"), _SCS("set_paused"), _SCS("is_paused") );
 	ADD_PROPERTY( PropertyInfo(Variant::INT, "stream/loop_restart_time"), _SCS("set_loop_restart_time"), _SCS("get_loop_restart_time") );
 	ADD_PROPERTY( PropertyInfo(Variant::INT, "stream/buffering_ms"), _SCS("set_buffering_msec"), _SCS("get_buffering_msec") );
+
+	ADD_SIGNAL(MethodInfo("finished"));
 }