Suggestion: Improve hashing strength on compatible systems

[phxql]

A PR which implements hashing with PBKDF2 SHA-256 had do be declined because Android doesn't support that algorithm.

Maybe we should implement a platform specific list of hash algorithms in a config to always select the strongest available. That way, a real Java application would get HMAC-SHA256 while Android stays on HMAC-SHA1.

Downsides: That way, a hash encoded with Heimdall on Windows can't be used anymore on Android, even if they hadve been created with the same Heimdall version.