Issue #1847682 by realityloop - Correct places to add directives in the Master Instance so they won't get blown away on update.

Issue #1544144 by thsutton - Use $server_name instead of $host in all sites/ paths to avoid broken URLs to static files for domain aliases in D7 (Nginx)

BOA: Introduce hot-swappable $key_uri for Speed Booster cache to allow forcing $args free $uri instead of default $request_uri (Grace)