support for GATE

[m-mcgowan]

This is a useful initiative! Having a common format for the different frameworks makes interoperability between NLP systems much more feasible without too much effort.

I'd like to suggest support for GATE, an NLP framework for Java. There is presently also a java implementation of JSON-NLP, which could make provide a starting point for building this.

I imagine this doesn't fall directly into the remit of this repo, but hope this can at least start a discussion about implementing it.