windows & osx untested bgm untested too many changes to comment on
implemented: [x] ingame menu [x] main menu [x] menus [x] fancy fades [x] structural earthquake [ ] the rest of the main menu (difficulty/char select)
load_textures() was changed to load_resources() and will now load all sounds in sfx/. playing via play_sound(char *name) (or the pointer variant). positional audio is not implemented yet. and some other changes.