TODO for the ImageJ 3D Viewer
===========================================================

* volume textures by ref.
* painting in 3D window
* ContentChangeBehavior
* improve UniverseListener
* SwitchInterpolator
* update macro language support
* update scalebar

* parallel projection
* Light sources
* remove axis -- done
* multiple selection
* printing

* Grouping

* Content hinzufügen ohne ensureScale and center