[stack] Cat version 0.9.9

I have released a new version of the Cat interpreter into the public
domain at http://www.cat-language.com/downloads.html . This version no
longer has a type-checker since the type-system was only just recently
redesigned to resemble ML more. I expect to reintroduce type-checking
gradually after version 1.0 until I have full support in version 2.0.

I have also updated the manual at
http://www.cat-language.com/manual.html and there is a draft of a
technical report at http://www.cat-language.com/paper.html / I'd love
to hear anyone's comments, suggestions, or criticisms.

Cheers,
Christopher Diggins
http://www.cdiggins.com