Added dbtk_tests.py; currently contains a test for Mammal Lifehistory.
Added dbtk_tests.py; currently contains a test for Mammal Lifehistory.

henrykironde/deletedret,davharris/retriever,henrykironde/deletedret,davharris/retriever,goelakash/retriever,davharris/retriever,embaldridge/retriever,bendmorris/retriever,bendmorris/retriever,goelakash/retriever,bendmorris/retriever,embaldridge/retriever,embaldridge/retriever