Various improvements

Some old commits I had in my workspace on Friday...

* Daybed init comments for blocks of code
* Replace error views messages
* Add tests for ``/token`` view (**pleaaaase**, follow "red green refactor" mantra)
* Fixed crash in ``/token`` when credentials are invalid
* Fixed ``credentials_id`` to be set on requests, without any check in anonymous views 

Commit log is clean, so reviewing by commit might be easier