zdtm: Move towards the new generation of criu testing (v3)

A little bit more stuff added :) With these changes I can run the

  zdtm.py run --all -x cgroup -x maps04 -x different_creds -x rtc

To run cgroups tests need to add .hook calls, for maps04 I don't have
enough RAM and disk in my VM (will fix), for different_creds need to
support crfail test option (dump _must_ fail), for rtc -- plugins.

So changes since v2:

1. Added exclusion (-x option)
2. Bugfix in parallel run
3. Fixed NS root permissions
4. Fixed checks for maps before and after dump
5. Fixed thread_bomb launch
6. Print test output
7. Support .checkskip scripts
8. Support features
9. Fixed test list

Andrey, thoughts?

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Andrew Vagin <avagin@openvz.org>