More beanstalkd removal & zmq fixing up

Fixed tests to pass again.

Removed more beanstalkd remnants.

The master can now take the ZMQ bind IP as an argument (instead of
having 0.0.0.0 hard-coded).  That way, if someone wants to be all
private and use 127.0.0.1 or some other single interface, they can.

Probably still need to fix the docs to fully reflect this change (and
update the pasted-in Usage messages, etc.).