qssb.h was a preliminary name and can't be pronounced smoothly.
exile.h is more fitting and it's also short. Something exiled is essentially
something isolated, which is pretty much what this library does (isolation from
resources such as file system, network and others accessible by system calls).
Refactor the test logic. Seccomp tests that can be
killed run in their own subprocess now.
All test functions now return 0 on success. Therefore,
the shell script can be simplified.
