Bottle-cork

* More flexible file naming in JsonBackend.
* Fixed function to update user's email address.
* More informative log message for missing Pycrypto.

* SMTP SSL support added, smtp_url parsing improved
* requirements.txt added.

* Check added to prevent multiple registrations of the same account

* PBKDF2 hash length check added
* Multi-platform unit testing

* SMTP URL added: support for STARTTLS, SSL and configurable port numbers
* Bug 10 fixed: login() redirects to fail_redirect if an username
is not provided
* Bug 11 fixed: better password hashing, multiple hash formats supported

* Improved package layout