Added beginnings of UnitTest framework

Started writing unit test cases using Visual Studio's built-in Test
Explorer. No external dependencies this way. clsAPIFileUtils now has
test cases. Two fail, but need need some discussion to resolve. This can
be deferred to a later time, the the users of these classes are
evaluated, and unit tests are generated for them - so we can
intelligently modify these base classes to better handle its expected
uses.