run.py: Add --overlay-rwdir flag

[zevweiss]

This allows the guest to have non-destructive (simulated) write access to parts of the host filesystem.

Signed-off-by: Zev Weiss [email protected]

[arighi]

This has been merged/fixed in https://github.com/arighi/virtme

NOTE: we are trying to catch up with all the pending PR in this temporary fork. In the future we may merge everything back here if this project become active again, but for now please consider to follow also the development of arighi/virtme.