Remove the os.user dependency and manually lookup /etc/passwd instead
Add unit test to check wrong uid case
Merge pull request #1096 from dotcloud/remove_os_user

* Runtime: Remove the os.user dependency and manually lookup /etc/passwd instead
Merge pull request #1208 from crosbymichael/1201-rw-volumes-from

- Volumes: Copy VolumesRW values when using --volumes-from
Do not overwrite container volumes from config

Fixes #819 Use same persistent volume when a container is restarted