Remove Ubuntu 13.10 as it is EOL as of July 17, 2014.
https://lists.ubuntu.com/archives/ubuntu-announce/2014-June/000185.html

Also removed dangling preseed.cfgs from previously EOL'd releases.
Merge pull request #245 from juliandunn/eol-ubuntu-13.10

Remove Ubuntu 13.10 as it is EOL as of July 17, 2014.