SLING-3709 - introduce new ModelFactory service interface which throws various exceptions based on failure conditions. Thanks to Konrad Windszus for the original patch!

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1628824 13f79535-47bb-0310-9956-ffa450edef68
SLING-3990 - Content Navigator does not correctly escape os names for
nodes with special characters

Fix and tests.

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1628826 13f79535-47bb-0310-9956-ffa450edef68