Patch: Added a cheats related log and cleaned up source code.

If any cheats file is not found, the "Not found Cheats file" message will appear with its full path of the cheats file on the log screen.

Changed some patch-related variable names. (1) Regular patches (or Game DB); (2) Cheats; (3) Wide screen patches (pnach); (4) Wide screen patches (zip); were difficult to distinguish them from their variable names. FYI: In some places of source code, "Patches" means (1), and "Cheats" means (2, 3 and 4).