Neverhood engine

Finally here's the pull request for the Neverhood engine some of you have been waiting for.

The facts:
- The game is completable, tested under Windows 7. I also played a few screens under Android.
- I did not test it on a big endian system.
- A run with Valgrind would be great, I'd be thankful if someone did that.
- The engine is feature complete. There's nothing missing unless I forgot something.
- The remaining work in-tree would consist mainly of bugfixing.
- I had to change the visibility for SmackerDecoder::_frameSizes from private to protected for a game-specific frame-exact seek to work.

Looking forward to your comments!