Modernization and bug fixing of Apple's AVCam sample project

Features:

• memory leaks free
• uses Automatic Referent Count (ARC)
• modern Objective-C syntax
• minor UI fixes for iOS 7

If you need to use the AVCam classes in a non-ARC project, you must selectively enable ARC on them. It can be easily achieved by adding fobj-arc to Other Linker Flags in your project's build settings.