add configuration ENV vars for the values that have been hard-coded
in the connector for zmq and the broker for zmq

the poll weight influences how many messages will be pulled from the
polling socket before it moves on to check the other socket, this is
currently 2/1 weighted in favor of the backend socket (the work
complete)

Also made a configuration value of the number of attempts to make on
getting the server uri on the client side
set default backend poll weight to 1 to not change behavior of current
break from frontend poll if queue is full
clean up the `run` method
Merge pull request #218 from localshred/abrandoned/config_zmq

Abrandoned/config zmq