tasks: Print out posix timers position

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
image: Add a few comments on time member

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
timers: Implement itimers conversion

This requires a bunch of kernel code to merge in.
Still there are no posix timers conversion since
we don't support them yet in criu.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>