separate creation and storage of mail tokens

`MailTokenBasedOperations#createToken` only creates a mailer token.

In turn, `handleStartSignUp` and `handleStartResetPassword` are
responsible for storage of the respective mail token.
Updated GoogleProvider to use the new Google endpoints
Upgrade to Play 2.3.3
Merge pull request #455 from benmccann/play-2.3.3

Upgrade to Play 2.3.3
Merge pull request #439 from normenmueller/feature/separate-mailtoken

separate creation and storage of mail tokens
- Added scalariform
- Separate creation and storage of mail tokens (thanks @normenmueller)
- Upgrade to Play 2.3.3 (thanks @benmccann)
Switched back to Play 2.3.2 because there are issues publishing signed artifacts with 2.3.3
Updated changelog: Switched back to Play 2.3.2 (problems publishing signed artifacts see https://github.com/sbt/sbt-pgp/issues/59)