Use consistent names for rendering matrices.

Adapt to changes in Rendering.
Adapt to changes in Rendering (renaming of matrices)
Adapt to renamed sg-uniforms.
LightNode: Add option to disableLights using a LightState.

LightNode: isSwitchedOn() added.
LightingState: get/setEnableLight(...) added.
...
LightNode: Adapt to changes in Rendering::LightParameters.
Transformations: Use references instead of pointers (they were not allowed to be null)
Transformations: Add rotateToWorldDir(...); Node: remove rotateToWorldDir(...) and lookAtAbs(...).
Node.get/setWorldPosition() -> Node.get/setWorldOrigin()
Rename Node transformation functions.

- getMatrix() -> getRelTransformationMatrix
- getSRT() -> getRelTransformationSRT
- getWorldMatrix() -> getWorldTransformationMatrix
- getWorldTransformationSRT() added.
- getScale() -> getRelScaling
- hasMatrix() -> hasRelTransformation
- hasSRT() -> hasRelTransformationSRT
- reset() -> resetRelTransformation
- resetRelRotation() added.
- setRelRotation( dir, up ) added.
- setScale(...) -> setRelScaling
- setMatrix(..) -> setRelTransformation
- setSRT(..) -> setRelTransformation
Old functions remain as deprecated aliases.

Transformations: getWorldSRT() remove (moved to Node)