Log Message:
Updated snd to 16.9.

Snd 16.9:

Anders Vinjar provided tankrev.scm
Tito Latini fixed a bug in clm's tap generator (discovered by AV).

Snd: removed snd13.scm

s7: make-keyword -> string->keyword

checked: FC 25, gtk 3.21.6 3.22.0|1, sbcl 1.3.10
  in gtk 3.22.0, the basic display mechanism changed again(!) so
  (at least today) the window-manager close decoration is messed up,
  and I probably missed other troubles -- please let me know
  as you encounter them.

Thanks!:  Anders Vinjar, IOhannes m zmölnig, Tito Latini.