ENH: update landmark registration

commit fbf515ecd91b26177bad25e0336c24deec8bf69b
Author: Steve Pieper <pieper@bwh.harvard.edu>
Date: Wed Oct 29 19:32:50 2014 -0400

ENH: improve the support for imported fiducial lists for LandmarkRegistration

- detect and set display style
- add associated node linkage
- avoid detecting storage nodes
- trigger registration when switching registration plugins

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23765 3bd1e089-480b-0410-8dfb-8563597acbee