Support binding outbound connections to a specific IP address

By passing (localaddr => $ipaddr) to VHost->new(), all outbound
connections will be made from the chosen IP address rather than
the host default
Client Quirks Support - Miranda

Deal with Miranda setting roster with a null id on the iq
Make S2S work for multi-domain

Need to track the origin domain as well, and cache separate connections
for each domain.  Can kinda see why I guess, but it's still annoying.
Would be nice to be canonical a bit like SMTP - where it's the MX server
that's used as the connection lookup key.
Send back the 'to' host as 'from' to the client for multidomain hosting

This is used where multiple domains are handled by the same
IP address, so we need to reply with the name that the
sender expects.
SSL - support different keys per vhost by localaddr binding
Connection: use USERDEBUGDIR environment variable to write XML DEBUG LOGs per user