Integrate OpenAL

[Daniferrito]

Integrate openAL into the engine. The graphics thread seems like a good place, as sound should not take too much resources.

The script to install OpenAL and link it is done alredy (in the physics branch, wich should be merged soon)

[bkloster]

On the backburner for now. Let's get some gameplay going before adding sound.

[jjonj]

I just managed to get music playing in-game after hacking at a branch for a little while, so i should be able to do a basic integration of openAL pretty easily.
I'm just not very familiar with the build system, so i'd like to know the proper way of having the build system link libOpenAL32.dll.a when compiling and copy the dll into the distribution (and whatever is required for linux).
You could do it instead to be safe, but i'd like to learn! I imagine it involves the setup scripts and cmake files.

I would just create a static class with basic functionality for playing wav files, which could later be augmented with more advanced functionality, multithreading etc.

If you're curious what i did to make it work:
I had notepad++ search all files in /build for C:\MinGW2\OgreSDK\lib\debug\libOgreMain_d.dll.a to which i took the link.txt and build.make files and manually added /.../libOpenAL32.dll.a, then i just needed to copy the dll already in MinGW, to the dist folder. Obviously not a very good solution.

[bkloster]

I actually had sound already implemented, albeit in a very old version of the engine. I just haven't gotten around to adapting it to the new structure yet, mostly because I consider sound a relatively low priority. In other words: I'll handle it, so don't invest too much time into it.

[jjonj]

Fair enough :)

[jjonj]

Closed with #86