Fix address in bindPandomPort.

Currently 'tcp://' is schema is set in Network.Transport.ZMQ so
bindRandomPort should not add it.
Use closeZeroLinger instread of close.

'closeZeroLinger' guarantees that socket will be closed immidiately,
without any timeout.
Close socket in monitor thread.
Remote unbind before socket close.

With new random port approach close after unbinds locks.
As close without explicit unbind is correct, we just use
it.
Merge pull request #14 from qnikst/random-port-fixes

Random port fixes