Change bbcleanup to function to allow testing, and add test class.
Add test for filtering file list to text files and code to pass the
test.
Refactor for testing. Still needs mocking of file IO to test
filterForContentFreeTextFiles method.
Merge pull request #1 from kwurst/tdd-refactor

Refactor for testing. Still needs mocking of file IO to test filterForContentFreeTextFiles method.