[FEA] NLTK Porter Stemmer

[VibhuJawa]

As a user i would like a porter stemmer in nvstrings as a important nlp pre-processing step.

Based a initial reading of the algorithm,

I feel implementing the measure function at a C++ level can be a good start as we may be able to implement the other functions on a python level.

Link to stemming logic: https://www.nltk.org/_modules/nltk/stem/porter.html

[davidwendt]

We are assuming that the nvstrings instance is individual words to measure:

• all lowercase
• no punctuation or whitespace
• English word rules apply (vowels, consonants, extra y-rule specified in the description's link) Let me know if this not correct.

[VibhuJawa]

This can be closed as measure was implemented in nvstrings.