HIL: we need very fast update of motor controls for HIL

When doing HIL with a copter you need to update the controls very
rapidly, much more so than with a plane. This puts the update in the
fast loop

git-svn-id: https://arducopter.googlecode.com/svn/trunk@1749 f9c3cf11-9bcb-44bc-f272-b75c42450872

ArduCopterMega/ArduCopterMega.pde

@@ -481,6 +481,11 @@ void fast_loop()
 	// write out the servo PWM values
 	// ------------------------------
 	set_servos_4();
+
+#if HIL_PROTOCOL == HIL_PROTOCOL_MAVLINK
+	// HIL for a copter needs very fast update of the servo values
+	gcs.send_message(MSG_RADIO_OUT);
+#endif
 }
 
 void medium_loop()