PQconninfo function for libpq

I'm breaking this out into it's own thread, for my own sanity if
nothing else :) And it's an isolated feature after all.

I still agree with the previous review at
http://archives.postgresql.org/message-id/1349321071.23971.0.camel@vanquo.pezone.net
about keeping the data in more than one place.

Based on that, I've created a different version of this patch,
attached. This way we keep all the data in one struct.

At this point, the patch is untested beyond compiling and a trivial
psql check, because I ran out of time :) But I figured I'd throw it
out there for comments on which version people prefer. (And yes, it's
quite possible I've made a big think-mistake in it somewhere, but
again, better to get some eyes on it early)

My version also contains a fixed version of the docs that should be
moved back into Zoltans version if that's the one we end up
preferring.

Also, a question was buried in the other review which is - are we OK
to remove the requiressl parameter. Both these patches do so, because
the code becomes much simpler if we can do that. It has been
deprecated since 7.2. Is it OK to remove it, or do we need to put back
in the more complex code to deal with both?

Attached is both Zoltans latest patch (v16) and my slightly different approach.

Comments on which approach is best?

Test results from somebody who has the time to look at it? :)

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/