Issue #11 CEventLoop uses QPointer trick to guard against use-after-free

See https://blogs.kde.org/2009/03/26/how-crash-almost-every-qtkde-application-and-how-fix-it-0

src/blackcore/airspacemonitor.cpp

@@ -182,7 +182,7 @@ namespace BlackCore
 
             // with this little trick we try to make an asynchronous signal / slot based approach
             // a synchronous return value
-            CEventLoop eventLoop;
+            CEventLoop eventLoop(this);
             eventLoop.stopWhen(m_fsdClient, &CFSDClient::flightPlanReceived, [ = ](const auto &cs, const auto &) { return cs == callsign; });
             if (eventLoop.exec(1500))
             {

src/blackcore/application.cpp

@@ -426,7 +426,7 @@ namespace BlackCore
     CStatusMessageList CApplication::waitForSetup(int timeoutMs)
     {
         if (!m_setupReader) { return CStatusMessage(this).error(u"No setup reader"); }
-        CEventLoop eventLoop;
+        CEventLoop eventLoop(this);
         eventLoop.stopWhen(this, &CApplication::setupHandlingCompleted);
         if (!m_setupReader->isSetupAvailable())
         {
@@ -435,6 +435,11 @@ namespace BlackCore
 
         // setup handling completed with success or failure, or we run into time out
         CStatusMessageList msgs;
+        if (!eventLoop.isGuardAlive())
+        {
+            msgs.push_back(CStatusMessage(this).error(u"Setup not available, already shutting down."));
+            return msgs;
+        }
         bool forced = false;
         if (!m_setupReader->isSetupAvailable())
         {

src/blackcore/db/backgrounddataupdater.cpp

@@ -152,7 +152,7 @@ namespace BlackCore::Db
             {
                 // just give the system some time to relax, consolidation is time consuming
                 if (!this->doWorkCheck()) { return; }
-                CEventLoop eventLoop;
+                CEventLoop eventLoop(this);
                 eventLoop.exec(1000);
             }
         }