Implements a basic reference counting mechanism.
Inherited By : DzAbstractAssetContainer, DzActivityLayout, DzAsset, DzAudioClip, brickset_dz, DzContentFile, DzContentFolder, DzDrawStyle, facegroup_dz, DzMaterial, DzMorphLoader, DzRSLShader, selectiongroup_dz, shaderbrick_dz, simulationsettingsprovider_dz, storable_dz, DzTexture, DzTextureModifier and DzWeightMap
Instances of DzRefCountedItem are objects that are intended to be shared between multiple owners. Each owner references the object when taking ownership, and dereference the object when it no longer needs the object. The object keeps an internal reference count, and when no other objects are referencing the object (i.e. the reference count reaches zero) the object will delete itself.