Modifying our API for `/register` to handle field validation.
Modifying our API for `/register` to handle field validation.

This means that if you've defined custom, required fields -- they'll be asserted
during POST requests to the registration API.

This would typically happen from something like an Angular.js or React.js client
creating a new account on a website.

stormpath/express-stormpath,stormpath/express-stormpath,stormpath/express-stormpath