iodine 0.5.2

This can be usable in different situations where internet access is firewalled, but DNS queries are allowed.
iodine runs on Mac OS X, Linux, FreeBSD, NetBSD and OpenBSD and needs a TUN/TAP device.
The bandwidth is assymetrical with limited upstream and up to 1 Mbit/s downstream.
The name iodine was chosen since it starts with IOD (IP Over DNS) and since
iodine has atomic number 53, which happens to be the DNS port number.
NOTE: iodine is licensed and distributed under the terms of the ISC license.

Main features:
- iodine uses the NULL type that allows the downstream data to be sent without encoding. Each DNS reply can contain nearly a kilobyte of payload data.
- iodine runs on many different UNIX-like systems. Tunnels can be set up between two hosts no matter their endianness or operating system.
- iodine uses challenge-response login secured by MD5 hash. It also filters out any packets not coming from the IP used when logging in.
- iodine handles setting IP number on interfaces automatically, and up to 8 users can share one server at the same time.

Enhancements
- Fixed client segfault on OS X
- Added check that nameserver lookup was successful
- Fixed ENOTSOCK error on OS X and FreeBSD