Add lb_method and health_check_request support

 * Add lb_method for selecting director load balancing method. It
   does not support the dns method.
 * Add health_check_request support. Required doing some string munging
   the vcl template.
 * Remove deprecation warnings from rspec-puppet 1.0.0
 * Sneak in some more documentation
 * Make health check params to really be defaults based off varnish docs