Patch #1622: Correct interpretation of various ZIP header fields.

Also fixes
- Issue #1526: Allow more than 64k files to be added to Zip64 file.

- Issue #1746: Correct handling of zipfile archive comments (previously
  archives with comments over 4k were flagged as invalid). Allow writing
  Zip files with archives by setting the 'comment' attribute of a ZipFile.
5 files changed