THREE.VRController.onGamepadDisconnect needs to be called when contro…

[lehoangphu]

…llers are removed.

The flow of the bug goes like this: . When the controller is connected, the gamepad object is saved at this.controller[x] . then when the controller is disconnected, the saved this.controller[x] is still in your array but the object is gone (all null) . then when the controller is reconnected again, it see that both gamepads[x] and this.controller[x] are both non-null so it does not update, then goes on to consume this.controller[x] which is already stale.

This change makes sure that we flush out the this.controllers array correctly.

[codefrau]

This fixes our exact problem. Please merge!

[lehoangphu]

@stewdio , can you merge this one?