Validate hook too limited

[KidkArolis]

I'd like to do some async validation and use app and some services to do so, but the default validation hook is only useful for very basic stuff that can be done locally with the data provided.

I started wrapping my validation in a higher order function to pass the app, but hooks/index.js that feathers generates are straight up functions.

[KidkArolis]

Suggestion, I guess, is to pass hooks as the 2nd arg to the validate fn in addition to data.

[eddyystop]

Noted. We've discussed doing a rethink of validation once the redesigned populate and serialize hooks are completed.

[eddyystop]

#109

This will be available in feathers-hooks-common v3.