LoadPlainText and LoadNYTimesXML: Simplify interface.
RefVariable: Put Value type member in better place.
PorterLemmatizer: Fix bug in TokenAnnotationString.
Rename ForwardCorefNer to NerForwardCoref, inline with naming scheme
everywhere else that puts adjectives as prefixes.
Additional comments.
Merge pull request #79 from andrewmccallum/nlpcleanup1

Various small NLP cleanups.  But it includes a renaming to NerForwardCoref, which will likely require a parallel change in factorie-nlp-resources.