Sends back request with password exchange

[KathrynmHansen]

Allows the request to be sent back with the password exchange.

[coveralls]

Coverage decreased (-0.1%) to 99.679% when pulling f8ef3b4 on KathrynmHansen:passwordRequest into 0516025 on jaredhanson:master.

[jaredhanson]

Could you describe the use case you are addressing with this patch?

In most cases, my recommendation when someone needs properties on the req object, is to attach them to req.authInfo in middleware before server.token(). What properties do you need? Understanding the context will help assess the best approach. Thanks!