Privileged mode + `tmpfs`

[Niek]

Would it be possible to add support for (and document) two important items:

• Running a container in privileged mode, so it's possible to run more advanced apps like Chromium?
• Mounting /tmp as tmpfs, so access to it is a lot faster compared to regular IO access?

The corresponding docker run flags would be: --privileged --tmpfs=/tmp.

Thanks!