Stop using the deprecated std::random_shuffle, for the benefit of MSVC.

And generalize `hrandom_shuffle` to take an arbitrary `Iter`,
so that passing `vec.begin()` will work even with MSVC's
debug iterators. (Passing `&vec[0]` or `vec.data()` would work
either way, but I'd worry that someone would forget to do that
conscientiously every time.)

game.cpp

@@ -4732,7 +4732,7 @@ void movehex(bool mounted, int colorpair) {
     for(int t=0; t<c->type; t++) if(c->mov[t] && inpair(c->mov[t], colorpair))
       dirtable[qdirtable++] = t;
       
-    random_shuffle(dirtable, dirtable+qdirtable);
+    hrandom_shuffle(dirtable, qdirtable);
     while(qdirtable--) {
       int t = dirtable[qdirtable];
       hexvisit(c->mov[t], c, t, mounted, colorpair);