retrieve a single entity by uuid or unique name
function(uuid_or_name, cb) {
        if (_.isObject(uuid_or_name)) { return cb(new Error('parameter must be a uuid or name')); }
        var self = this;
        client.getEntity({ type: self._usergrid.type, uuid: uuid_or_name }, translateSDKCallback(function (err, entity) {
          if (err) { return cb(err); }
          cb(null, wrap(self, entity));
        }));
      }