BUG: Fixed IdentifyIslandEffect on transformed segments

When IdentifyIslandEffect was applied on a transformed segment, the result was incorrectly transformed.
The reason was that vtkMRMLSlicerSegmentationsModuleLogic::ImportLabelmapToSegmentationNode(vtkOrientedImageData*, ...)
assumed the labelmap was in the world coordinate system.
A better assumption is that the labelmap to be imported is in the same coordinate system as the segmentation node.
Described the current behavior in the method's documentation.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@25445 3bd1e089-480b-0410-8dfb-8563597acbee