Adapt to changed bower dependencies.

 + cryptojs is available as a bower package. We don't need to provide a custom
   ZIP.
 + Apparently, bootstrap has moved the font files. Update Gruntfile to copy new
   font.
Decouple localStorage.

The localStorage is going to be replaced with a Firebase integration. This
decoupling makes writing this integration easier.
Switch to Firebase as storage.
Rename and split modules.

Split login module into login and core module. Prepend passio modules with
"passio".
Use strict.
Clear text fields after adding password.
Switch to custom REST backend.

As the Firebase backend provides no suitable authentication mechanism, we have
to switch to a custom backend. The user's authentication is now verified by
deriving an authentication token from the users password. This is done by
hashing the password 80,000 times with SHA-256. As calculating 80,000 SHA-256
hashes requires some time, the login screen is shown for a couple of seconds
after clicking "Login".