Fix crash on shutdown

StopAllMacros was called before th->wait(), allowing Macro::Stop()
to run concurrently with the other threads still inside
CheckConditions. This caused races on _conditionCheckFuture (called
from both threads) and _helperThreads.

This could happen if conditions / actions were marked to run in parallel
to the main loop.

lib/advanced-scene-switcher.cpp

@@ -461,12 +461,13 @@ void SwitcherData::Stop()
 		SetMacroAbortWait(true);
 		GetMacroWaitCV().notify_all();
 		GetMacroTransitionCV().notify_all();
-		StopAllMacros();
+		SignalStopAllMacros();
 		StopAndClearAllActionQueues();
 		CloseAllInputDialogs();
 		th->wait();
 		delete th;
 		th = nullptr;
+		WaitForAllMacros();
 		RunStopSteps();
 	}