Make process asynchronous about nlp.js

[vvscode]

@jesus-seijas-sp except changing an interface - nothing else should be changed? right?

[jesus-seijas-sp]

@vvscode Correct. The problem is that is a breaking change so it will mean a major version, an also affect to so many tests.
The idea is that the interface must be prepared so the ner-manager instead of using microsoft recognizer that is sync, can use call to apis like duckling.

[vvscode]

I'm taking it

[DiegoRBaquero]

I would like to point out that even if using async/await, train method blocks completely the event loop. In my API server, requests stop being received until training is done