Bruteforcing/cracking unknown rotors with rotors - Kriegsmarine model

[Alexthemediocre]

It should be made more clear in the README that to solve for unknown rotors including VI, VII, and VIII, kriegsmarine_model should be passed to smart_decipher/bruteforce_decipher instead of m3_model. I was under the impression that m3_model would have contained the extra rotors, based on some other tools.

[the-lambda-way]

Good point. I am thinking about whether to make Kriegsmarine the default M3 in the future.

I added some comments to the README in commit c126b34.