Update virtualjoystick.js

Removed VirtualJoystick.prototype._onUp	= function()
{
	this._pressed	= false; 
	this._stickEl.style.display	= "none";
	this._baseEl.style.display	= "none";
	
	this._baseX	= this._baseY	= 0;
	this._stickX	= this._stickY	= 0;
}