#2551: include RePriMand in the ET

Comment (by Roland Haas):

Once RePrimAnd is compiled by default (or also before if you like, I can always enable its build on Jenkins) you could set up a "repo push" (the default) web-hook to contact https://einsteintoolkit.org/hooks/repo_changed.php?secret=XXX to send commit messages to commits@einsteintoolkit.org where XXX is to be found in https://bitbucket.org/einsteintoolkit/www/src/master/hooks/repo_changed.php#lines-18 (or thereabouts, look for the variable $secret).