<MatzeB> -cleanup in resource management functions

<MatzeB> -cleanup in resource management functions
<MatzeB> -fixes 3 potential crashs (deleting Sprite classes, using member function in
<MatzeB>     BadGuy class after removing it)
<MatzeB> -cleans up sound init code and hopes that calling Mix_AllocateChannel will make
<MatzeB>  SDL_mixer happy...
<MatzeB> -fix paths that missed a / after DATADIR
<MatzeB> at least valgrind doesn't report any errors anymore when you apply that patch
<MatzeB> (memory errors though, not memory leaks)

SVN-Revision: 737