Adding GOLD_NER_BIO view to Textannotations in file

[nitishgupta]

I will write the code to add a NER_GOLD_BIO view to TextAnnotation.

This view unlike the NER view, will have all sentences and all tokens as constituents. The labels for the constituents will be the BIO labelling for NER. This will help us in creating StructuredProblem object in illinois-sl and also in evaluating by making a similar NER_PRED_BIO view.

Also, BILOU will be easy to extend.