re-resolve tcp addresses on reconnections

Resolve the address on `add_reconnect_timer`, to tolerate DNS changes.

This might look expensive but in reality, the code eventually calls `InetAddress.getByName` which is cached internally in the jdk and also configurable, (see http://stackoverflow.com/questions/12099526/setting-java-dns-cache-ttl) so not only you get tolerance to DNS changes but also respect what the user chose as it's DNS ttl timeout.

Note: the patch removes some extra whitespace, to focus on the important part of the patch add ?w=1 to the url:

https://github.com/zeromq/jeromq/pull/129/files?w=1