stemmer : disambiguate prefix rule 27
stemmer : disambiguate prefix rule 28
stemmer : disambiguate prefix 29
stemmer : disambiguate prefix rule 30
stemmer : disambiguate prefix rule 32
disambiguate prefix rule 34
stemmer functional test : test combiination of prefix + suffix
stemmer : fix regex
functional test : stem complex combination of prefixes
stemmer : recursively remove prefix