Do not set the user transform directly.
Rolled back scale matrix calculation.

Instead gives back full transformation. Also removed test case as it is
now invalid.
Added Transformation class to hold metadata for the transformations.
Collection of changes.

- Transformations are now stored and managed in a list.
- Added overlay to multi render widget.
- Added histogram for ray profile of TwoStepPicker.
- Transformations are saved to project.