docs: function toCallback(cbo, reserve) {
  	if (!cbo[0] && !cbo[2]) return cbo[1];
  	
  	if( typeof(reserve) === "undefined" ) {
  		return function () {
  			_call(cbo, arguments.length?Array.prototype.slice.call(arguments):null, true);
  		}
  	}
  
  	if( !reserve ) {
  		return function () {
  			_call(cbo);
  		}
  	}
  
  	return function () {
  		var arg= Array.prototype.slice.call(arguments,0,reserve);
  		if( arg.length<reserve ) arg= arg.concat(new Array(reserve-arg.length));
  		_call(cbo, arg, true);
  	}
  }