This adds a new execution driver for Docker which will use lmctfy. Docker can be
instructed to use lmctfy driver by passing the flag ‘-e lmctfy’ on startup of
the docker daemon.
This driver requires lmctfy version 0.4.5 or greater to be
installed. (https://github.com/google/lmctfy).

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Added tty support to lmctfy driver. Fix /dev/shm to be a private tmpfs. Capture errors from creaper. Fixed the mount setup to include missing pty related mount points.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Added support for environment setup and fixed the way user command is passed to work with /bash -c "arg" kind of input.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)