red-black tree: use explicit leaf nodes

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
red-black tree: can delete from a tree with 1 node

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
red-black tree: can now delete from tree with 10 items

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
red-black tree: delete works

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
red-black tree: use cache for latest node

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
red-black tree: clarify some code

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
scripts: support header in actor profiles

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
implement fair actor scheduler in Thorium

Link: https://github.com/GeneAssembly/biosal/issues/701
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>