Support native JSON in scripts

// mode=local,language=javascript,datatype='text/plain; charset=utf-8'
var addr = cacheManager.getAddress();
{address: addr}

// mode=local,language=javascript,datatype='application/json;type=java.lang.String'
cache.put({k: "բարեվ"}, {v: "բարեվ"});
cache.get({k: "բարեվ"});

// mode=local,language=javascript,datatype='application/json; charset=utf-8'
var s = cache.size();
var st = cache.getStatus();
{size: s, status: st}