DOC: Prevent concept checking comments from being parsed by Doxygen

The comments for "Begin/End concept checking" are not API documentation
and should not start with "/**", which triggers parsing by Doxygen.

This fixes a bug where the function definition immediately following the
"End concept checking" line gets improperly documented.

Change-Id: I91d66f3888c505ffebc55a3d4a75b53ac5b9be03
BUG: Prevent DCMTK from trying to build unnecessary components

Some components of DCMTK are unnecessary to ITK, but enabled by default.
These should be explicitly disabled, preventing warnings if DCMTK fails
to build them.

Change-Id: Ib20b23bdfc369e6ec6a906598eb7e0f4fe86d24d
Merge topic 'DCMTK-warnings'

0f37ee0 BUG: Prevent DCMTK from trying to build unnecessary components
Merge topic 'ConceptChecking-Comments'

17030da DOC: Prevent concept checking comments from being parsed by Doxygen