CIDR addresses in pg_hba.conf

here is a patch that allows CIDR netmasks in pg_hba.conf. It allows two
address/mask forms:

. address/maskbits, or
. address netmask (as now)

If the patch is accepted I will submit a documentation patch to cover it.

This is submitted by agreement with Kurt Roeckx, who has worked on a patch
that covers this and other IPv6 issues.

cheers

andrew