Modified jobTest to be compatible with setupJobTree being a context manager. Make explicit calls to __enter__ in setUp() and __exit__ during teardown().
Modified jobTest to be compatible with setupJobTree being a context manager. Make explicit calls to __enter__ in setUp() and __exit__ during teardown().

BD2KGenomics/slugflow,BD2KGenomics/toil-old,BD2KGenomics/slugflow