public void step(int numUpdates)
{
for (int t = 0; t < numUpdates; t++) {
foreach (TestableGameObject o in toAdd) {
objects.Add(o);
}
toAdd.Clear();
foreach (TestableGameObject o in toRemove) {
objects.Remove(o);
}
toRemove.Clear();
foreach (TestableGameObject obj in objects) {
obj.Update();
}
}
}