Tune abort

* Added code to restore tune button to off / colors when
    sound card right channel change interrupts transmit cycle

src/waterfall/waterfall.cxx

@@ -1234,6 +1234,10 @@ void waterfall::set_XmtRcvBtn(bool val)
 {
 	FL_LOCK_D();
 	xmtrcv->value(val);
+	if (!val && btnTune->value()) {
+		btnTune->value(0);
+		btnTune->labelcolor(FL_FOREGROUND_COLOR);
+	}
 	FL_UNLOCK_D();
 }