Delete prototype code
Delete prototype code

 - Deleted experimental monoid and functor instances because there was
   no real use for them. The types they were for ended up being better
   described as type synonyms.

 - Deleted prototype NGram type because while it did carry information
   about the phrasal component, the information wasn't actually
   accessible for later computation. The accompanying Functor and Monoid
   instances were also deleted.

R-Morgan/NGramCrackers