thorium: print tag in hexadecimal

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
thorium: isolate code that inspects the queue

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
thorium: fix bug in inbound message regulator

The patch 58c6811
("thorium: add a communication regulator for inbound messages")
contains an implementation bug and therefore does not regulate
anything. The problem was that the flag
FLAG_REGULATOR_IS_ENABLED would simply toggle rapidly from 0 to 1.

Link: https://github.com/GeneAssembly/biosal/issues/740
Link: https://github.com/GeneAssembly/biosal/issues/709
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>