code: function validateMetadata(metadataPath, cb) {
    validateJSonStructure(metadataPath, function(err, metadataObject) {
      if (err) {
        cb(err, null);
      } else {
        cb(null, metadataObject.files);
      }
    });
  }
docs: Validates the metadata.json file
  
  @param {string} metadataPath path to themetadata.json file
  @param {function} cb callback