The use of the `QmitkMxNMultiWidget` is currently not possible due to missing axial, sagittal, coronal, 3D render windows and missing multi widget planes.
a0b88fba introduced a new function that access the render windows by using the view direction.
For more changes concerning the new view directions, see T26543
This new access leads to a lot of changes, which will be listed here:
As long as these changes are not merged to master, a workaround will be implemented: The `"axial"`, `"coronal"` etc. strings will be transformed into the corresponding view direction.