Use @SafeVarargs and add a little more documentation.
Separate out some regex Patterns. Separate out some regex Patterns (maybe only in String form) to their own class, so that using them doesn't require loading a GrammaticalRelation(s) class. This will facilitate having different implementations of EnglishGrammaticalRelations to start supporting Universal Dependencies. Also document some of the non-null-ness of things in EnglishGrammaticalStructure, and remove must-be-true tests.
Oops, forgot to add new file.