Prepare for bump v0.9.1

This PR adds the following cherry-picked PRs to the bump_v0.9.1 branch:
https://github.com/dotcloud/docker/pull/4000
https://github.com/dotcloud/docker/pull/4499
https://github.com/dotcloud/docker/pull/4504
https://github.com/dotcloud/docker/pull/4563
https://github.com/dotcloud/docker/pull/4603
https://github.com/dotcloud/docker/pull/4604
https://github.com/dotcloud/docker/pull/4621
https://github.com/dotcloud/docker/pull/4624
https://github.com/dotcloud/docker/pull/4656
https://github.com/dotcloud/docker/pull/4658
https://github.com/dotcloud/docker/pull/4659
https://github.com/dotcloud/docker/pull/4676
https://github.com/dotcloud/docker/pull/4698
https://github.com/dotcloud/docker/pull/4702
https://github.com/dotcloud/docker/pull/4710
https://github.com/dotcloud/docker/pull/4720
https://github.com/dotcloud/docker/pull/4723
https://github.com/dotcloud/docker/pull/4739

This PR is going to be merged into the bump_v0.9.1 branch.