add sanity checks for attempting to get/set non-positive window dimensions.  trying to figure out why a call to SDL_SetVideoMode would crash
add sanity checks for attempting to get/set non-positive window dimensions.  trying to figure out why a call to SDL_SetVideoMode would crash


kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1