ANN: PostgreSQL syntax mode for Vim

I've created a PostgreSQL syntax mode for Vim. This will colorize pgdump
files and hand-crafted SQL files for PostgreSQL.

It is based on, and still similar to, the generic SQL mode for Vim. It
adds many PG-specific keywords, operators, and such.

To use this, copy the file to your $VIMRUNTIME/syntax or personal .vim
syntax directory (in Unix, that's usually $HOME/.vim/syntax; in Windows,
usually c:\vim\vimfiles\syntax). Open a PG file and :set filetype=pgsql.

Two items on the TODO list are:

* Handle functions better. Right now, the entire body of the function is
treated as a string. Would be nice to have it colorized internally.

* Handle psql SET statements better. I'm finding it difficult to
distinguish these from UPDATE.. SET.. statements.

I'd be happy to get any feedback, etc., from anyone. After a round of
feedback and clean-up, I'll find a suitable place to post & maintain it.

Thanks!

- j.