Command repeating by using cmd queues

This replaces the old pushq/saveq arrays (which were used to save
the keys pressed by the user for repeating a previous command)
with a new command queue.  This means there's no hard-coded limit
to the saved keys, and it can repeat extended commands which are
not bound to any key.

src/potion.c

@@ -2299,7 +2299,7 @@ dip_into(void)
     struct obj *obj, *potion;
     char qbuf[QBUFSZ];
 
-    if (!cmdq_peek()) {
+    if (!cmdq_peek(CQ_CANNED)) {
         impossible("dip_into: where is potion?");
         return ECMD_FAIL;
     }