Replace GamepadViewer link with HTML5GamepadTester

HTML5 Gamepad Tester uses the same API but provides technical info about the control surfaces, which is much more useful for development.

Author: dmadison

README.md

@@ -23,7 +23,7 @@ Before the library will work, you must install a compatible boards file that con
 
 After installing a compatible boards package, you must then [download and install the library](https://www.arduino.cc/en/guide/libraries). Once the XInput library is installed, open up the Arduino IDE and load an example sketch, located in `File -> Examples -> XInput` (I suggest trying the 'Blink' sketch first). Double-check that you have the correct XInput board selected in the 'Tools' menu, then upload the sketch to your microcontroller.
 
-On Windows, you can test that the sketch is working properly by opening up the joystick control panel ([joy.cpl](https://support.microsoft.com/en-us/help/831361/how-to-troubleshoot-game-controllers-in-microsoft-games)) or by using [GamepadViewer.com](https://gamepadviewer.com). If you uploaded the XInput 'Blink' example, the #1 button ('A') should be slowly turning on and off.
+On Windows, you can test that the sketch is working properly by opening up the joystick control panel ([joy.cpl](https://support.microsoft.com/en-us/help/831361/how-to-troubleshoot-game-controllers-in-microsoft-games)) or by using [HTML5 Gamepad Tester](https://html5gamepad.com/). If you uploaded the XInput 'Blink' example, the #1 button ('A') should be slowly turning on and off.
 
 ## Control Surfaces