World: Disconnect the MapConversionReporter once map editing ends

Once editing has ended when converting a map in some other format
we are no longer interested in being notified of any issues.

doomsday/client/src/world/world.cpp

@@ -694,7 +694,7 @@ bool World::changeMap(de::Uri const &uri)
     Map *newMap = d->loadMap(uri);
 
     // The map may still be in an editable state -- switch to playable.
-    if(newMap->isEditable())
+    if(newMap && newMap->isEditable())
     {
         // Configure a reporter to observe the process.
         /// @todo Make the reporter available during the format conversion.
@@ -708,6 +708,10 @@ bool World::changeMap(de::Uri const &uri)
         // Output a human-readable log of any issues encountered in the process.
         reporter.writeLog();
 
+        // We are no longer interested in reports about this map.
+        newMap->audienceForOneWayWindowFound   -= reporter;
+        newMap->audienceForUnclosedSectorFound -= reporter;
+
         if(!mapIsPlayable)
         {
             // Darn, clean up...