More robust result checks.

All returns from OpenAL are now checked. A failure will cause the affected object to abort construction. This includes OALSimpleAudio.
This means that you must check the result of [OALSimpleAudio sharedInstance] at least once to be sure it successfully constructed.
Restructured file layout.

ObjectAL (iOS) -> iOS
ObjectAL (OSX) -> OSX

All ObjectAL specific files have been moved to the ObjectAL directory.
Changed the demo to use cocoapods for cocos2d.
Updated podspec to 2.3
MIT license
Merge github.com:kstenerud/ObjectAL-for-iPhone