ENH: expose parameter in Bilateral filter

This commit addresses JIRA issue #2996.

The parameter m_DomainMu from the BilateralImageFilter is exposed.

Moved the constructor implementation to the hxx.

Updated the tests to specifically set m_DomainMu, to test this function.

Change-Id: I1c80ae6abe067d6ae8b4f61a95cef6432db38036
BUG: Regressions with respect to building DCMTK

1. The wrong hash tag was given to check out DCMTK
from https://github.com/InsightSoftwareConsortium/DCMTK

2. Erroneous conditional inclusion of statements in
Modules/ThirdParty/DCMTK/itk-module-init.cmake

Change-Id: I313bdf5c1b3dacc81a2d8b2f73dd8a9b5ad3e322
Merge topic 'Fix_DCMTK_PATCH_Regression'

31bc608 BUG: Regressions with respect to building DCMTK
Merge topic 'BilateralFilter'

fd2fab1 ENH: expose parameter in Bilateral filter