Updated the crypto engine:

- Updated AES and SHA-1 source code;
- Fixed a few code warnings;
- Implemented EDAT/SDAT decryption.

Started SPURS implementation:
- Added an internal SPURSManager class draft;
- Added several drafts for cellSpurs functions.

Implemented key.edat decryption in sceNpDrmIsAvailable:
- NOTE: Currently, the decrypted key.edat is stored under dev_hdd1/titleID and the user must replace this file in dev_hdd0. This behavior will change in the future as it's currently intended for controlled testing only.