Add new tests directory with some unit tests  for dataBank class

This is the beginning of adding unit and functional tests for OSCAAR.  
There are a few unit tests here for dataBank, as well as placeholders for additional tests for that class.

I'd also like to move the tests.py for the GUI over to this tests/unit_tests directory, if you approve.

I don't know how to get rid of the commit that I had to sync my fork with the main code.