BUG: Fix fiducial labels are too far away from the glyphs in the 3D view.

See Slicer3 bug 0000806 at http://www.na-mic.org/Bug/view.php?id=806

Widgets/vtkAbstractPolygonalHandleRepresentation3D.cxx

@@ -589,9 +589,9 @@ void vtkAbstractPolygonalHandleRepresentation3D::UpdateLabel()
                          (bounds[3] - bounds[2]) * (bounds[3] - bounds[2]) +
                          (bounds[5] - bounds[4]) * (bounds[5] - bounds[4]) );
     this->GetWorldPosition(labelPosition);
-    labelPosition[0] += width * xAxis[0];
-    labelPosition[1] += width * xAxis[1];
-    labelPosition[2] += width * xAxis[2];
+    labelPosition[0] += width/2.0 * xAxis[0];
+    labelPosition[1] += width/2.0 * xAxis[1];
+    labelPosition[2] += width/2.0 * xAxis[2];
     
     this->LabelTextActor->SetPosition(labelPosition);