enable user to switch on/off the connectors.

Many installations use Tomcat behind an Apache Web Server
so these don't need keystores, SSL or HTTP connectors.

This patch introduces three new parameters "use_http_connector", "use_ssl_connector" and "use_ajp_connector"
that switch on/off (defaults to "true" to keep previous behaviour) the respective connectors
added description of the master switches to the README.md