Abrandoned/thread backtraces

1. Alpha several methods primarily in the zmq connector
2. Elevate the zmq broker polling milliseconds on the select call to an ENV var "PB_ZMQ_BROKER_POLLING_MILLISECONDS"
3. Add SIGTRAP to the trapped signals in zmq server so `kill -s TRAP pid` will log the backtrace of each thread
4. Fix "bug" with stats that always logs the first server as the server chosen from the client side when multiple servers are avail, the stats host/port needed to be reset if another server is chosen by the beacons, ping port (maint) or the first alive load balancing

@localshred 
I'm fine with the change, `tap` can be useful for certain situations but here I don't think it aids in readability any, especially because of the call to `end.string`, which to me is kind of awkward (says the guy who wrote it).