message: fix frame accumulation
  currentAccum was being incremented twice per frame
diff: @@ -71,6 +71,8 @@ void Frame::startNewFrame(bool interacting)
  if (immediatelyWait)
  waitOnFrame();
  + if (!accumLimitReached())
  + currentAccum++;
  }
  }
  @@ -97,8 +99,6 @@ void Frame::waitOnFrame()
  auto future = value().valid() ? handle() : nullptr;
  if (future)
  future.wait(OSP_FRAME_FINISHED);
  - if (!accumLimitReached())
  - currentAccum++;
  }
  void Frame::cancelFrame()
  