ArduinoOutput.cpp: Fix enable() and disable().

Fixes caught by -Wreturn-type.

Have enable() properly return a value. Have disable() actually disable
the Arduino, and then properly return a value.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

Source/Processors/ArduinoOutput.cpp

@@ -118,16 +118,18 @@ bool ArduinoOutput::enable()
 
         std::cout << "Arduino is initialized." << std::endl;
         arduino.sendDigitalPinMode(13, ARD_OUTPUT);
-
+		return true;
     } else {
         std::cout << "Arduino is NOT initialized." << std::endl;
+		return false;
     }
 }
 
 bool ArduinoOutput::disable()
 {
-
-
+	if (arduino.isInitialized())
+		arduino.disconnect();
+	return true;
 }
 
 void ArduinoOutput::process(AudioSampleBuffer &buffer,