adding unit test for dbm_demo
2nd attempt at making dbm_demo unit test
pep8 changes and removing try,except clauses (including from test_sdae.py)
removed old imports, added skip_if_no_data
moved skip into test_sda, test_dbm, train_dbm functions
Merge pull request #584 from capybaralet/master

adding unit test for dbm_demo