code: public static File zip(File... files) {
          try {
              File temp = File.createTempFile("osgl", ".zip");
              zipInto(temp, files);
              return temp;
          } catch (IOException e) {
              throw E.ioException(e);
          }
      }
docs: Zip a list of files into a single file. The name of the zip file
  is randomly picked up in the temp dir.
  
  @param files
  the files to be zipped.
  @return a file that is a zip package of the `files`