Savedata Encryption/Decryption

[Hykem]

As requested, I've added a better handling of SAVEDATA files.
As of r3435 JPCSP looks for a specific bit on the PARAM.SFO file (a similar check is performed on a real PSP) and auto-detects the SAVEDATA format, so you no longer need to enable/disable any options.

The "Disable SAVEDATA encryption" option is still there, but it's now oriented for developers to test data.

Without changing any option, JPCSP does the following:
Plain data (unencrypted) detected -> Load the data directly -> Data is changed by the application -> Write encrypted data
Encrypted data detected -> Decrypt and load the data -> Data is changed by the application -> Write re-encrypted data

But, if you check the "Disable SAVEDATA encryption", JPCSP does:
Plain data (unencrypted) detected -> Load the data directly -> Data is changed by the application -> Write plain data (unencrypted)
Encrypted data detected -> Decrypt and load the data -> Data is changed by the application -> Write plain data (unencrypted)

This way, you can force JPCSP to output decrypted data, which means you can use JPCSP to output your SAVEDATA in encrypted or decrypted format.
Combining this with the "Extract SAVEDATA key" options gives you all the necessary tools to modify, decrypt and encrypt your SAVEDATA, either with JPCSP, PPSSPP, or any external tools.

I've also improved the algorithm and the hashing routines, fixed Java issues and a few other bugs. I would really appreciate any reports on these new changes, specifically if there are any improvements with PSP compatibility. Thanks!