move EngineEffectRack cration to addToEngine()
Clear rack lists in EffectChainManager::~EffectChainManager()
Remove EngineEffects and EngineEffectsRack directly when engine thread is already down
delete request if EffectsManager::writeRequest() fails to add message
delete EngineEffectChain when removing from rack
delete WTrackTableView::m_pTrackInfo