Cracker control

This is actually Level 17, it's just that Level 17 itself is tiny in comparison to the "password cracker" control I had to make in order to do it.

This also fixes a bug where, on level 18, going to the scene where the phone is front-and-center leads to a crash.
It also replaces the phone on level 18 with a better looking one, and also the textfield on the computer of level 18 with a BGKVTextFieldPasswordControl (which essentially just looks nicer and is semantically cleaner).