libpq object hooks patch

Here is an updated version of the object hooks patch. It now supports a
list of hooks for a PGconn, and PGresult. This had to re-introduce the
concept of hook name. Being that there is now a list, you need a way to
reference an item of that list.

Also added PQobjectHooks and PQresultObjectHooks, to get a pointer to
the conn or result hook list. PQmakeResult must allow the ability to
pass a list of object hooks in. So, PQresultObjectHooks was born.
pqtypes doesn't need (at least at this time) PQobjectHooks but leaving
it out felt unbalanced.

Note: PQhookData and PQresultHookData can be removed. There
functionality can be reproduced by an API user issuing PQobjectHooks or
PQresultObjectHooks and manually looking for there hook (normaly to get
at the hook->data). Basically, an API user would do themselves what
PQhookData is doing.

--
Andrew Chernow
eSilo, LLC
every bit counts
http://www.esilo.com/