Adding RunIn to run a user specified command in an existing container, wait for it to exit and return the exit code.
RunIn will connect to a user specified Terminal before running the command.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Updated RunIn API to match the new console handling behavior in HEAD.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
'nsinit exec' now uses namespaces.RunIn instead of namespaces.ExecIn.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Fix runin code for nsinit
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Merge pull request #64 from vishh/runin

Adding RunIn to run a user specified command in an existing container.