use flags in node

Link: https://github.com/GeneAssembly/biosal/issues/572
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
use flags in actor

Link: https://github.com/GeneAssembly/biosal/issues/575
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
rename BSAL_ACTOR_ to THORIUM_ACTOR_

Link: https://github.com/GeneAssembly/biosal/issues/576
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
report an error if the -o directory already exists

Link: https://github.com/GeneAssembly/biosal/issues/571
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
check if there is a test for kmer length value

Link: https://github.com/GeneAssembly/biosal/issues/564
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>