thorium: show if multiplexer is disabled

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
thorium: add option to enable metadata tracking for actors

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
red-black tree: reuse normal nodes

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
thorium: catch SIGKILL and SIGTERM

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>