Switch akka-zeromq to use the pure java JeroMQ implementation.

I understand from https://github.com/akka/akka/issues/13856 that this
change may or may not be desired.  However @chrisdinn asked for a PR.  Here ya go...  We have been using this change with the current 'stable' JeroMQ 0.3.4 on a production server with success.  All Akka unit tests pass with this change.

Thanks for the great work!