Pyroute2

Release candidate. Added optional async I/O thread in `NetlinkSocket`. IPDB restarts on I/O errors and when sync is lost.

Release candidate. The first version completely w/o iocore and rpc. New simplified architecture, increased performance, (supposed to be) more stable (but we'll see ;)

The new module layout. Utilities `IPRoute` and `IPDB` moved to `pyroute2`; all the netlink protocols moved to `pyroute2.netlink`.

The release is the intermediate step before the new approach, where all the netlink providers are simple threadless (but threadsafe) socket objects, and all the «cluster-oriented» code is deprecated. The new architecture one can review at the `master` branch, expected `0.3.2` release time — the end of November.