#7 Brat fixed for new `NE` and `Relation`

[keighrim]

This addresses #7 .

• For NamedEntity, the values of"label" field are used as label in the brat
  • This will break Brandeis services, until lappsgrid-services/edu.brandeis.cs.stanfordnlp-web-service#10 and lappsgrid-services/edu.brandeis.cs.opennlp-web-service#8 are fixed.
  • dkpro wrapper would be fixed later with other bugfixes
• For Relation the values of "label" field are used as label for the relation itself, and everything in "features" except for features.pred will be seen as arguments, presumably only two exist.
  • This will work with both representation suggested from the discussion in #7 .

[keighrim]

I'm merging this as it appears to meet all the requirements discussed in #7 . There will be more fixes needed later, so I'll keep the branch for further changes.