[stack] Status of Cat and CVML

Quick Cat/CVML update.

I am currently working on the next generation of Cat, which will use
the Cat virtual machine language (CVML). CVML is an optimizing
bytecode compiler developed from scratch in C++ and is hosted at
http://cvml.googlecode.com. The current version is not yet ready for
public consumption (undocumented, fragile, and non-portable). It is
going be used as the back-end for the next Cat interpreter version.

I am also working on adding portable continuations to Cat and CVML. I
expect to have the first prototype done by mid-February at the latest.
There are opcodes being introduced into the bytecode to allow
continuations (implemented by cloning the current VM state) to be
created, cloned, and serialized over a stream or network. In addition
I am adding an event passing mechanism to allow VM instances to
communicate safely and asynchronously.

I am also working on a paper for LCTES 09 about using CVML to generate
compact byte-code. From my preliminary results CVML appears to be
significantly smaller (space savings of 50% or more) over other
byte-codes. Anyone interested in reviewing please drop me a line.

- Christopher