Made some changes towards working sound. Code is still very hacky but at least some code now
compiles (sample.cc).

Current versions of MikMod and allegro conflict because of type SAMPLE so i moved sound code to
new module sound.cc/sound.h.

sample.h was removed entirely and contents merged to module sound.

I still haven't made a makefile because I'm not sure which buildsystem will be used for this project.

I will make another commit for changes in ai.h engine.h volcano.cc and items.h.
Some sound related changes. More like placeholders than working code.