controller hangs when no files are provided

Link: https://github.com/GeneAssembly/biosal/issues/194
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
add children acquaintances

Link: https://github.com/GeneAssembly/biosal/issues/184
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
spawn sequence stores in round robin order

Link: https://github.com/GeneAssembly/biosal/issues/183
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>