add experimental low-latency mode

do not use (yet)!

src/engine/platform/vrc6.cpp

@@ -429,6 +429,7 @@ int DivPlatformVRC6::getRegisterPoolSize() {
 void DivPlatformVRC6::reset() {
   for (int i=0; i<3; i++) {
     chan[i]=DivPlatformVRC6::Channel();
+    chan[i].std.setEngine(parent);
   }
   // a poll may be necessary to decide the default
   chan[2].vol=30;