BUG: Fix #3585. Python bool('string') == True for any non-empty string

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22891 3bd1e089-480b-0410-8dfb-8563597acbee
COMP: Update OpenIGTLinkIF to fix TDATA segfault

For reference, see:

  https://github.com/openigtlink/OpenIGTLinkIF/pull/23

and

  https://github.com/SlicerIGT/OpenIGTLinkRemote/issues/18

From: Isaiah Norton <inorton@bwh.harvard.edu>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22892 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: Implemented GetMarkupIndexByID and GetMarkupByID methods

From: Laurent Chauvin <lchauvin@bwh.harvard.edu>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22893 3bd1e089-480b-0410-8dfb-8563597acbee