supervisor: Tighten up the seccomp blacklist
supervisor: Add --seccomp-dump-pfc

This is useful for debugging the filter.
supervisor: Change seccomp bad arch action from KILL to ENOSYS

Killing the process is gratuitous, especially for x32 syscalls.
supervisor: Tighten up ptrace restrictions in devmode
Merge pull request #44 from amluto/master

Tighten up the seccomp sandbox