public WebApiSearch addCacheAttributes(final CacheAttribute... ca) {
            cacheAttributes.addAll(Arrays.asList(ca));
            return this;
        }
filters for given cache attriutes. Only positive attributes can be filtered, no exclude possible
TODO does not work with V1, only works with V2!
main/src/main/java/cgeo/geocaching/connector/gc/GCWebAPI.java