Pulled out login/logout logic from SiteController.

Now the account related information goes into an account controller.
This allows us to separate account specific details such as login, logout,
reset and modification from everything else.
Preparation for multiple user types.

Refactored login and logout into Account Controller.

Updated User schema and UserIdentity to facilitate multiple user types.

Added a basic registration form to assist testing of multiple users.

Allow access to dbgen.php through 127.0.0.1/PVMS/protected/data/dbgen.php
to reset database to default state while testing.

Modified schemas to match changes in User.