Add functions for decoders to return latency statistics

moonlight-common/src/com/limelight/nvstream/av/video/VideoDecoderRenderer.java

@@ -7,6 +7,10 @@ public interface VideoDecoderRenderer {
 	
 	public int getCapabilities();
 	
+	public int getAverageEndToEndLatency();
+	
+	public int getAverageDecoderLatency();
+
 	public boolean setup(int width, int height, int redrawRate, Object renderTarget, int drFlags);
 	
 	public boolean start(VideoDepacketizer depacketizer);