Failures due to build order of Slicer CAT with superbuild remote modules

[jamesobutler (James Butler)]

I found the following example which may be the way to update extensions source without having to maintain a fork with the hack.

COMP: Fix bundling of OpenIGTLinkIO external project adding VTK dependency

Also here was my original post on this topic from a couple years back. SlicerOpenIGTLink causing CustomApp build to fail