Diminish error marker prominence

Don't render ESM4 actors or SpeedTree objects

apps/openmw/mwclass/esm4base.hpp

@@ -150,11 +150,8 @@ namespace MWClass
 
         std::string getModel(const MWWorld::ConstPtr& ptr) const override
         {
-            // TODO: Not clear where to get something renderable:
-            // ESM4::Npc::mModel is usually an empty string
-            // ESM4::Race::mModelMale is only a skeleton
-            // For now show error marker as a dummy model.
-            return "meshes/marker_error.nif";
+            // TODO: Implement actor rendering. This function will typically return the skeleton.
+            return {};
         }
     };
 }

components/resource/scenemanager.cpp

@@ -726,6 +726,11 @@ namespace Resource
         auto ext = Misc::getFileExtension(normalizedFilename);
         if (ext == "nif")
             return NifOsg::Loader::load(*nifFileManager->get(normalizedFilename), imageManager);
+        else if (ext == "spt")
+        {
+            Log(Debug::Warning) << "Ignoring SpeedTree data file " << normalizedFilename;
+            return new osg::Node();
+        }
         else
             return loadNonNif(normalizedFilename, *vfs->get(normalizedFilename), imageManager);
     }