Added missing nls comments
Changed layer list and elevation model update to propogate up the layer tree
Moved draw order sorting directly into the AbstractLayerTreeNode, instead of having a custom scene controller
Enabled blending in the atmosphere ground layer
Allowed nullable draw order in getLabel method
Disabled sun layer writing to depth buffer when drawing final fullscreen quad
Added firing of property change event when layer list changes
Switched to working DoubleClickZoomListener
Added more default layer class -> draw order definitions
Added draw order viewer to layers panel