Support naming containers when creating them

Add support for passing in the name parameter to the call to
/containers/create to name the created container (API v1.6 feature).

Signed-off-by: Maxime Petazzoni <max@signalfuse.com>
Add integration test for named container creation

Signed-off-by: Maxime Petazzoni <max@signalfuse.com>
Merge branch 'named-container-create' of github.com:mpetazzoni/docker-py into mpetazzoni-named-container-create
Added unit test for named containers