send salt on Session#create without srp ephemeral A
send more meaningful error message on completely failed login attempt
fixed tests to use setup and teardown blocks
make sure user tests also run when run from users subdir

* The APP_CONFIG needs to be initialized in core so that is required from other engines
* paths for load_views need to be relative to the model - not to rails root.
Merge pull request #41 from azul/feature/allow-getting-salt

Allow getting salt and proper error messages for invalid login attempts