IPv6 support core changes

I've reimplemented ipv6 support, this time in the 0.9 branch. I'll look into configuring custom regular expressions from now on.
My changes tested correctly, but I noticed some other tests from servertestcase, clienttestcase and samplestestcase still failed on my system (FreeBSD 9.1, python 2.7.5), but that was also the case with my unchanged checkout of branch 0.9