This module applies the Porter Stemming Algorithm to its parameters,
returning the stemmed words.

The algorithm is implemented exactly as described in:

    * http://snowball.tartarus.org/russian/stemmer.html

The code is carefully crafted to work in conjunction with the Lingua::Stem
module by Benjamin Franz. This stemmer is also based on the work of Aldo
Capini, see Lingua::Stem::It.