OAK-690: Enforce and clarify Root contract wrt. invalid Tree instances
Don't call API / overrideable method from constructor

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1455171 13f79535-47bb-0310-9956-ffa450edef68
OAK-691: Error while moving a node if the destination is not connected

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1455172 13f79535-47bb-0310-9956-ffa450edef68