Proper fix for stringcase and add unit test

[andy31415]

This fixes the breakage in #23 and adds a unit tests and fixes the case for the spacing that the original attempt for fixing addressed.

[andy31415]

Overall I am unsure about stringcase and pascalcase test coverage. current pip install does things like:

>>> import stringcase
>>> stringcase.camelcase('THIS_IS_A_TEST')
'tHIS_IS_A_TEST'
>>> stringcase.camelcase('With Some Spaces')
'witompaces'
>>>

Which seem somewhat unexpected. Ideally I would get thisIsATest or withSomeSpaces .... seems we may go down a rabbit hole here.