Pingerd is now dhmonpinger Python module.

This is because I'm having trouble with ZMQ and want to use RabbitMQ
instead. This is the first step towards that - given that the C libraries
for RabbitMQ is hugely more complex than for ZMQ I want to use Python for
that part.
Updated clients for pinger to use the new MQ way

Also made example into a pingerlib.