iOS Device identifier

This code return the exact device on NSLOG, compare the NSString platform to execute the appropriate code for each device.

Works on all iOS version.

Use it on cocos2d to resolve a memory warning on iPod Touch 4th generation (iPod1,1 - iPod2,1 - iPod3,1 - iPod4,1)

Feel free to reuse, copy or adapt this code without limitations.