Update Dockerfile to be based on 13.10 instead of 12.04 so that we can remove our s3cmd backports need, and so we can have the new linux-libc-dev dependency we need for compiling the btrfs driver without nasty APT hackery

In addition, we've now hard-coded LXC version 0.8 compiled from source so that we can have the most stable dev environment possible.

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #3796 from tianon/dockerfile-btrfs

Update Dockerfile to be based on 13.10 instead of 12.04, add linux-libc-dev dep, remove s3cmd backports nonsense