Log Message:
Update to 1.18:

1.18 Wed 25 Oct 2006 - Adam Kennedy
  - Changing to a production version for final release
  - No other changes of any kind

1.17_05 Tue 19 Sep 2006 - Adam Kennedy
  - Seperated the classes from the main file into seperate packages.
  - Merged the Zip.pod into the main Zip.pm file.
  - Applied default Perl::Tidy to all of the source files, to improve
    the readability and maintainability of the files.
  - Added license in Makefile.PL
  - Added some additional entries to the realclean files