Fixed bug to decide if a document is a accesss document.
Change the key of unaccessablesubtree from subtreeid to startnodeid. because some subtree doesn't have subtreeid.
Change a method name to mergeEquivlentSubTree.
Add code to handle if a unaccessable subtree is another subtree of unaccessable subtree.
Fixed a bug to check permission for a node.
Add code to handle check a node permission for subtree access control.
Change the debug level.
Add the code to handle subtree access control.
Add a file to handle permission checking.