[IMPROVED] Unlock notification mails on auto-locks

* Added new token type: account_unlock
* Added update SQL File
* Updated base structure with new token type
* Added empty template
* Updated user class to send mail on failed passwords
* Added unlock account page to use tokens

Addresses #670
[ADDED] Account unlock mail on failed PIN
Merge pull request #1213 from TheSerapher/issue-670-unlocks

[IMPROVED] Unlock notification mails on auto-locks