new annotations ns that prepares us for larger api.

[leontalbot]

We will need to create tests for the hole core ns and run those before we can merge this PR. This annotations namespace introduce all the core annotations implementations we need to grow our api and cover most of corenlp api.

[damienstanton]

Thanks, @leontalbot 👍

Per my other comment I'll try to get the tests finished up and will merge this PR once the tests are done.

[leontalbot]

Excellent! Thanks!