* Don't start if udp port is really closed
* Fully check all udp ports
* Remove test code.......
* Add tests and adjust impl a bit
* Add comment
* Move comment a bit
* Move a bit
* clean ups
--gossip-port now specifies exactly that, the gossip port to use. The
new --gossip-host argument can be used to specify the DNS name/IP
address for gossip if --entrypoint is not supplied (when --entrypoint is
supplied, the gossip address is automatically set to the node's ip
address as observed by the entrypoint)