Allow the user to provide his own sockets

The automatic construction of ZMQ sockets is very limited currently. Instead of
forcing ourselfs to always keep up to date with whatever kind of socket options
ZMQ and its perl bindings offer and exposing them explicitly ourselfs, allow our
consumer to take control of construction of sockets if he wishes to.

Again, this is based upon the latest version of this distribution on CPAN, 0.005, as the latest code in the master branch is referencing code not yet available on either CPAN or Message-Passing's master branch.