* Runtime: use --numeric-owner for Tar and Untar

* Hack: remove dependency of unit tests on 'os/user', which cannot be used with CGO_ENABLED=0

+ Documentation: Add terminology section

fix regression in utils tests introduced by #980

Fixing hack/Vagrantfile to use uname for aufs linux extras

Conflicts: hack/Vagrantfile
Resolved by: Daniel Mizyrycki <daniel@dotcloud.com>

Bump version to 0.4.6

- Runtime: fix a bug which caused creation of empty images (and volumes) to crash.

Remove dependency on 'os/user', which cannot be used with CGO_ENABLED=0. This allows running the tests without CGO.

Packaging|Ubuntu, issue #526: Follow init permission pattern for docker.conf

Bump version to 0.4.5

+ Client: Add docker ps -s option to display containers' sizes

Improve Docker build

Remove code unreachable using Go 1.1

* Client: fix progressbar output

891 mark command as optional for docker run

* Makefile: Add link flags in order to link statically and without debug symbols

* Auth: fix auth small issue in case you change your password on index.io

fix typo in documentation