rename test/ to tests/ because there are many tests

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
add ") {" to check.sh

Link: https://github.com/GeneAssembly/biosal/issues/42
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
add test for get() in hash table

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