fix "is a directory" test to actually test that, retaining old test under a better name
fix "is a directory" test to actually test that, retaining old test under a better name

jmurzy/nodegit,jmurzy/nodegit,nodegit/nodegit,nodegit/nodegit,nodegit/nodegit,jmurzy/nodegit,nodegit/nodegit,jmurzy/nodegit,nodegit/nodegit,jmurzy/nodegit