…er into .cpp to avoid possible issues with imports/exports under Windows build.
… is already pullled via ViewerBase
… ON, some exports are still missing on osgPresentation::AnimationMaterialCallback and osgUtil::IncrementalCompileOperation::CompileSet."
…te destruction of singleton mutexes.
…curred when nodes in parental chain of a newly loaded node had been deleted.
… dedicated ObserverSet class, which utilises a global recursive mutex that is dedicated to manage Observer and ObserverSet. The new global mutex for observers avoids problems with deadlocks that were occurring previously when an osg::Refenced object was being deleted at the same time as on osg::ObserverNodePath.
…hing of an observer_ptr<> every frame. Changed include to point to new Observer header
… overlap with window resize handler.