Major (interface) changes (#60) -- big thanks @iburago!!:
 - Read from an abbreviations file only when invoked from command line
 - Rename and refactor the create_wordlist_filter() function

Minor changes:
 - #63: Do not capitalize small words occurring within hyphenated word groups (thanks @iburago!)
 - #65: Always capitalize 'Mc'-prefixed small words in compound word groups (thanks @iburago!)
 - #67: Don't capitalize Mr, Ms, Mrs (thanks @GurraB!)
 - #71: Add Manifest.in and include license file in src dist (thanks @synapticarbors!)