remove(item) {
        let result = this._queue.remove(item);
        let index = this._repeat.indexOf(item);
        if (index != -1) {
            this._repeat.splice(index, 1);
        }
        if (this._current == item) {
            this._current = null;
        }
        return result;
    }
Remove a previously added item
@param {?} item
@returns {bool} successful?