PERF: 0004191 update landmark registration

New version avoids some duplicated work when interacting
with fiducial lists and displayable managers.

See:
https://github.com/pieper/LandmarkRegistration/commit/b6198147a57f2fe50aa9ac40194e67064a14a524

From: Steve Pieper <pieper@isomics.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@25172 3bd1e089-480b-0410-8dfb-8563597acbee