Disallow installation unless SSL is configured properly with browser-valid certificate
Created by: kenrestivo
Do not allow the installation wizard in mod/setup.php to proceed via HTTP.
Test SSL first via curl, re-using code already in setup.php, report error if it's not configured, stop installation.
Transparently and/or manually redirect to HTTPS url if the SSL passes the test.
Allow a manual flag in .htconfig.php or similar for testing and development purposes, to disable this test when needed.