clear(withZombies = true) {
            for (let zombie in this._zombiesLoaded) {
                this._zombiesLoaded[zombie].destroy();
            }
            for (let tile in this._tilesLoaded) {
                this._unloadTile(tile, true, undefined);
            }
            this._tilesLoaded = [];
            this._zombiesLoaded = [];
            this._zombiesLoadedCount = 0;
            this._cachesLoaded = [];
            this._cachesLoadedCount = 0;
        }
Delete all data in the cache
@param {boolean} withZombies