add experimental command stream player

for verification

after that I am going to write optimization code

src/engine/playback.cpp

@@ -1385,6 +1385,15 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
     }
   }
 
+  if (subticks==tickMult && cmdStreamInt) {
+    if (!cmdStreamInt->tick()) {
+      cmdStreamInt->cleanup();
+      delete cmdStreamInt;
+      cmdStreamInt=NULL;
+    }
+  }
+
+
   firstTick=false;
 
   if (shallStop) {