Fix creating symlinks in make-macosx-app.sh

Create symlink if arch name is found anywhere in info printed by file command, not only if arch name is the last word.
Fix text getting appended to vid_restart in command buffer

I was getting unknown command "vid_restart-button2" warning on OSX when trying to use alt-return to toggle fullscreen.
Remove 5 unused variables from make-macosx scripts
Fix OpenAL music stop issues using stream stop code

S_AL_StopBackgroundTrack would sometimes generate AL errors.
S_AL_MusicSourceFree needs to kill source or next track may have short looping buffer.
Fix "bind <key>" message for unbound keys

"bind X cmd; unbind X; bind X" now says '"x" is unbound' instead of '"x" = ""'