BUG: Improve module Group membership detection.

Use the EXCLUDE_FROM_DEFAULT option in the module definition to determine if
a module should be enabled by its group membership by default.

This fixes, for example, IODCMTK enablement on Windows.

ITK-3284

Change-Id: Ifc6fac43dcffa6891fa00b8b06a1147225408d8e
Merge topic 'IODCMTKDefault'

62375c00 BUG: Improve module Group membership detection.