Add allow-origin as payload data within the ciphertoken

[jonasdacruz]

I've been thinking in ways to make easier the improvement of the security of the ciphertoken usage. I think, it would be interesting if we could append information about the allowed origins to use each token.

In the step of token creation we could add one or more possible origins and embed them in the ciphertoken payload.

We could force to send the origin and forbid using this concrete token from other origins.