#2176: Test "Binary neutron star" example

Comment (by Atul Kedia):

There is some issue with the nsnstohmns.th thornlist that is disrupting the download of NSTracker. The issue, as I understand, is that http://einsteintoolkit.org/gallery/bns/nsnstohmns.th accesses the link https://svn.cct.lsu.edu/repos/numrel/$1/$2/trunk which is dead and needs to be replaced with a new one.

I last downloaded ET with the nsnstohmns.th a couple weeks ago and all went well, so this must have come up recently.