creates and entity or entities immediately on the server w/ attributes and returns the entity / entities attributes may be an attribute object or an array of entity objects or attribute objects
function(attributes, cb) {
        if (_.isArray(attributes)) {
          var self = this;
          for (var i = 0; i < attributes.length; i++) { // validate all
            var each = attributes[i];
            var entity = (this.isInstance(each)) ? each : self.new(attributes[i]);
            if (!entity.isValid()) { return cb(entity.getErrors()); } // todo: collect all entities errors?
          }
          client.batchCreate(this._usergrid.type, attributes, function(err, entities) { // create with single call
            if (err) { return cb(err); }
            var wrapped = _.map(entities, function(entity) {
              return wrap(self, entity);
            });
            cb(null, wrapped);
          });
        } else {
          this.new(attributes).save(cb);
        }
      }