net: give better error messages

Add address and/or port to errors where applicable for better reporting.
In the event the local address and port are accessible, it will also add
those to the error message.

See joyent/node#7005
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
PR-URL: https://github.com/iojs/io.js/pull/35