Added DEFGENERIC form for GET-NEXT-EVENT.
Added DEFGENERIC form for DISTRIBUTE-EVENT.
Added DEFGENERIC form for INVOKE-WITH-PORT-LOCKED.
Added DEFGENERIC forms for {ADD,DELETE,RESET}-WATCHER.
Added DEFGENERIC form for MAKE-GRAFT.
Added DEFGENERIC form for PORT-LOOKUP-PIXMAP + comment.
Removed commented-out code.