added unit tests; tested code against python 2 and 3 using tox; formatted...

added unit tests; tested code against python 2 and 3 using tox; formatted python code using PEP8 style guide; removed config file

CONTRIBUTING.rst

@@ -77,7 +77,7 @@ Ready to contribute? Here's how to set up `data2passcal` for local development.
    tests::
 
     $ python -m unittest (or python -m unittest tests.test_data2passcal under Python2)
-    
+
 6. Commit your changes and push your branch to GitHub::
 
     $ git add .