ACCESS: Support for Amazon - Guardians of Eden

This is a pull request for the game Amazon - Guardians of English. It uses the Access engine, which was used for several games, so it may well end up supporting more games in the future. Currently, it supports both the floppy and CD versions, as well as the demo. The game is completable, although further gameplay testing is required. There are only a few things left to do for the game:
* Some polishing of the sound/music/voice playback code.
* Dirty rect list isn't enabled yet. The game has a dirty rect list, but it's not yet being used.
* There are a couple of spots in the game that the original implements things in a way that I'd consider to be bugs, that I'd prefer fixing under ScummVM.

Source-wise, the code is pretty solid, with everything already nicely re-factored into separate classes for the various parts of the engine, and we've already spent some effort to keep Amazon game specific code separate from the core engine, so hopefully it won't be too hard to add support for further games in the near future.

I'm pretty sure this is only casting to char to silence some warnings on systems where char is signed. If there's characters encoded by values > 127, the code printing them will need to simply cast the individual characters of the String to byte again before using them in arithmetic or similar. So, this probably applies to different places than this one.