BUG: Fix vtkImageBimodalAnalysis to work with any input scalar type

Following kitware/VTK@238163f, the vtkImageAccumulate filter has been
fixed to work with large images by changing its output type from "int"
to "vtkIdType".

Considering that

(1) the output of the vtkImageAccumulate filter was the input of
the vtkImageBimodalAnalysis filter

and

(2) the vtkImageBimodalAnalysis "ExecuteData" function didn't specify
the vtkIdType scalar type in its list of hard-coded switch cases

The window and level computed by the bimodal filter were 0 and the ad-hoc
approach was then used to compute the windows and level.

This commit fixes the problem by updating the bimodal filter to use
the vtkTemplateMacro avoiding to systematically list all cases.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23908 3bd1e089-480b-0410-8dfb-8563597acbee