Re #457: audio working in Companion, Simulator and simu using SDL library (use SIMU_AUDIO=YES to enable)

Re #457: case insensitive f_stat() and f_open() for SIMU

radio/src/simu.cpp

@@ -134,6 +134,7 @@ Open9xSim::Open9xSim(FXApp* a):
 Open9xSim::~Open9xSim()
 {
   StopMainThread();
+  StopAudioThread();
   StopEepromThread();
   
   delete bmp;
@@ -430,6 +431,7 @@ int main(int argc,char **argv)
   printf("Model size = %d\n", (int)sizeof(g_model));
 
   StartEepromThread(argc >= 2 ? argv[1] : "eeprom.bin");
+  StartAudioThread();
   StartMainThread();
 
 #if defined(PCBTARANIS)