COMP: Add test to verify Slope/Intercept handling

This patch was originally supposed to add explicit
slope/intercept processing in ImageIO, but once I added a
test to verify the proper behavior, I discovered that
Slope/Intercept are handled in the DCMTK library.

At any rate this patch fixes A) a couple of small problems
in DCMTKImageIO that kept the new test DICOM files from
being read correctly, and B) there's now a test that
explicitly verifies slope/intercept processing.

Change-Id: I692a8e10c0260e321b2230e746b8c14e58753d57
ENH: Removing const_casts from ImageRegistrationv4 tests

Change-Id: Iee49c3ce55de986627ee2a61a421a7a21db9ceb5
BUG: GDCM reporting wrong spacing for some Media Types

Noticed and reported by Andriy Federov.  Andriy encountered a dataset
that reported spacing of 1,1,1, when the actual spacing was 0.178038,
0x.174924, 1. I traced the problem to some tortured logic in
gdcmImageHelper.cxx.  Since that is a 3rd party library, I modified
itkGDCMImageIO.cxx to work around the problem rather than fix the
version of GDCM in ITK.

Change-Id: I3ebfc828da36bca86d78123cedb29b0e88aca4c7
BUG: Add AllocateOutputs method to other v4 RegistrationMethods

This allows for the Setting of the InitialTransform to be copied to
the output.

Change-Id: I7d03a6a367c85b1a5294a01e34f36ce962472bc6
ENH: Update v4 registration tests to set initial transform

It is not standard behavior for a process object to use an output an
an initial value for processing. These tests are changed so that the
input "InitialTransform" is use for the transform to start
registration with.
BUG: Remove old itkSampleBuildTest.cmake.in file.

This unmaintained file has been replaced by files on the "dashboard" branch.

Change-Id: I9f9af200a2ae5351519396486a504cb33f5ccad0
Merge topic 'DCMTK_SlopeIntercept'

5bf3754b COMP: Add test to verify Slope/Intercept handling
Merge topic 'GDCMSpacingFix'

168c457e BUG: GDCM reporting wrong spacing for some Media Types
Merge topic 'FixRegistrationMethodv4TestsForConstCorrectness'

17a02024 ENH: Update v4 registration tests to set initial transform
a2a735f7 BUG: Add AllocateOutputs method to other v4 RegistrationMethods
be07ec72 ENH: Removing const_casts from ImageRegistrationv4 tests
Merge topic 'FalseDashboard'

d1472f57 BUG: Remove old itkSampleBuildTest.cmake.in file.