new type: document label?

[Dmitriy Dligach]

We've recently been using cTAKES more and more for document-level 
classification (e.g. phenotyping). Would it make sense to add a new type 
(that would derive from TOP) to store the label for a document? I know 
we currently have a doc id for each document, but having the label type 
would simplify a lot of things (e.g. debugging).

Thanks,
Dima