Added new Host mode Audio Class driver.

Added new EVENT_Audio_StreamStartStopChange() event to the Audio Device Class driver to detect stream start/stop events.

LUFA/Drivers/USB/Class/Device/Audio.c

@@ -70,6 +70,7 @@ void Audio_Device_ProcessControlRequest(USB_ClassInfo_Audio_Device_t* const Audi
 				Endpoint_ClearStatusStage();
 
 				AudioInterfaceInfo->State.InterfaceEnabled = ((USB_ControlRequest.wValue & 0xFF) != 0);
+				EVENT_Audio_StreamStartStopChange(AudioInterfaceInfo);
 			}
 
 			break;
@@ -164,4 +165,9 @@ bool Audio_Device_ConfigureEndpoints(USB_ClassInfo_Audio_Device_t* const AudioIn
 	return true;
 }
 
+void Audio_Device_Event_Stub(void)
+{
+
+}
+
 #endif