Update tornado/netutil.py

`socket.getadrrinfo` yields some strange output if Python is compiled with `--disable-ipv6`, resulting in a `bad family` error.
See http://bugs.python.org/issue16208
Add vagrant config for ubuntu 12.10.

This release is interesting because it includes a python3 port of
pycurl (which is difficult to use from tox but can at least be tested
manually).
Preliminary support for ubuntu's python3-pycurl port.
Merge pull request #670 from schlamar/patch-1

Fix bind_sockets when python is compiled with --disable-ipv6
Document --disable-ipv6 fix and only apply it when family==AF_UNSPEC.
Get twisted_test running on python 3 too.

Twisted 12.3.0 can be installed from a source checkout on python3.
Some modules, including twisted.web, are not available so skip those
tests separately.