Merge branch 'master' into feature/memory-allocations

# Conflicts:
#	include/openspace/scene/scenegraphnode.h
#	modules/imgui/include/gui.h

include/openspace/rendering/renderengine.h

@@ -179,8 +179,6 @@ private:
     Camera* _camera = nullptr;
     Scene* _scene = nullptr;
 
-    properties::BoolProperty _doPerformanceMeasurements;
-
     std::unique_ptr<Renderer> _renderer;
     RendererImplementation _rendererImplementation = RendererImplementation::Invalid;
     ghoul::Dictionary _rendererData;