This partially nails this TODO item:
* Add schema, cast, and conversion backslash commands to psql
I had to create a new publically available function,
pg_conversion_is_visible, as it seemed to be missing from the catalogs.
This required me to do no small amount of hacking around in namespace.c
I have updated the \? help and sgml docs.
\dc - list conversions [PATTERN]
\dC - list casts
I didn't support patterns with casts as there's nothing obvious to match
against.
I've tested it a fair bit and I can't see any problems. Feel free to do a
once over on my backend changes tho.
Chris
