Don't add empty gamepads

src/init.coffee

@@ -3,7 +3,7 @@ $(document).on("viewinit", () ->
   salet.view.gamepads = []
   jQuery.ajax({
     dataType: 'json',
-    url: 'mappings.json',
+    url: salet.view.gamepadmappings,
     success: (data) ->
       salet.view.gamepadmappings = data
       window.addEventListener("gamepadconnected", (e) ->
@@ -14,6 +14,7 @@ $(document).on("viewinit", () ->
       )
       if (typeof navigator.getGamepads == "function")
         for pad in navigator.getGamepads()
-          salet.view.gamepads[pad.index] = new Gamepad(pad)
+          if pad?
+            salet.view.gamepads[pad.index] = new Gamepad(pad)
   })
 )