Update notes for submitted changes

* Added all the different node types required
* Got basic sphere rendering working
* Moved grouping from Node to GroupNode
* Another change to the API, making geometry nodes
* Got triangle mesh rendering to work again
* Rename the rendering geometry classes
* Merge remote-tracking branch 'origin/master' into rendering-scene-graph
* Migrated the picking code to the geometry node
* Addressed points raised in code review