CYKLO-927 Remove StemmerPL, Factory will produce its own wrapper.
CYKLO-927 Return anonymous class which wraps StempelStemmer. I think less codebase (no StempelPL) is a good thing.
CYKLO-927 Change contract
CYKLO-927 Use new contract. It should be faster because there is no need for creation of additional String or even two String objects - one here and one inside old StemmerPL
CYKLO-927 Update test