SLING-3776 - refactor to prepare for more rendering options

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1613070 13f79535-47bb-0310-9956-ffa450edef68
SLING-3786 - more refactoring

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1613074 13f79535-47bb-0310-9956-ffa450edef68
unused variable

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1613075 13f79535-47bb-0310-9956-ffa450edef68