New Build Errors on CDash 1/24/18 - drop support for VS2013 in ITKv5?

@hjmjohnson @matt.mccormick

That is a good list a features for the VS compilers.

We have more failures on the dashboard now. Here are some new VS12 2013 errors:
https://open.cdash.org/viewBuildError.php?buildid=5238580

This is because VS12 does not support constexpr. So it looks like we are going to drop support for that compiler too?