OAK-798: Review / refactor TreeImpl and related classes
deprecate Tree.getLocation
deprecate Root.getLocation

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1478206 13f79535-47bb-0310-9956-ffa450edef68
OAK-798: Review / refactor TreeImpl and related classes
Replace usage of Root.getTreeOrNull with Root.getTree

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1478208 13f79535-47bb-0310-9956-ffa450edef68