Added a Windows Gaming Input joystick driver

This driver supports the Razer Atrox Arcade Stick

Some of the quirks of this driver, inherent in Windows Gaming Input:
* There will never appear to be controllers connected at startup. You must support hot-plugging in order to see these controllers.
* You can't read the state of the guide button
* You can't get controller events in the background

src/joystick/SDL_gamecontroller.c

@@ -1045,7 +1045,7 @@ static ControllerMapping_t *SDL_PrivateGetControllerMappingForNameAndGUID(const
     }
 #endif /* __LINUX__ */
 
-    if (!mapping && name) {
+    if (!mapping && name && !SDL_IsJoystickWGI(guid)) {
         if (SDL_strstr(name, "Xbox") || SDL_strstr(name, "X-Box") || SDL_strstr(name, "XBOX")) {
             mapping = s_pXInputMapping;
         }