[Koha] Z39.50 testing

[Tonnesen Steve]

To those of you who have been testing the Z39.50 interface on
142.28.224.14, you should know that some other Koha features on that
machine are badly broken at the moment.  I'm working on integrating full
MARC record support on that machine, so things like editing records are in
a sad state.  In particular, I know that Modifying a biblio record will
result in an internal server error, although it will successfully modify
the biblio record and the underlying MARC record before returning the
error.  :)

I've changed the z39.50 querying daemon so that it will fork up to 20
separate processes for doing queries.  This speeds up the results
considerably. I've also set up a new database table so that additional
Z39.50 servers can be added for different Koha installations quite easily.

Thanks to everyone who's been testing this and pointing out my obvious
mistakes.  :)

Steve.