Re: proposal \gcsv

Here's a WIP patch for the parenthesized-options route.

I realized that if we make the options be single words in the form
name=value, we can easily handle the shortcut forms with no value.
So that's what this does.

What this does *not* do is offer any solution to the question of
how to put a right paren as the last character of a pset option
value.  I don't really see any easy way to handle that, but maybe
we can punt for now.

Also no docs or test cases, but I see no point in putting effort into
that in advance of consensus that this is what we want.

0001 is some save/restore infrastructure that we'd need for pretty
much all of the proposals on the table, and then 0002 improves the
command itself.

                        regards, tom lane