backend: check nodes/items permission on disco#items: - move node access check workflow from getItemsData to a new checkNodeAccess method - only accessible items are returned to an entity when doing a disco#items on a node - for PEP, nodes with presence access model are not returned if entity has not presence subscription from the node owner - all nodes are returned in normal pubsub service - new NotLeafNodeError exception when an action need to be done on Leaf node and it is not the case - /!\ access it not fully checked : items access models are not handled for items id in disco#items, and whitelist nodes are returned regardless if requestor is in the white list or not. Furthermore, publisher-roster access is not handled for nodes.

v. 0.2 (02/12/2015):
	- schema updated (unversioned => version 1)
	- sync with Idavoll
	- use of sat.tmp.wokkel as a workaround for change not merged upstream
	- RSM (XEP-0059) implementation
	- MAM (XEP-0313) implementation
	- Namespace Delegation (XEP-0355) implementation
	- Privileged Entity (XEP-0356) implementation
	- removed remote-roster hack
	- SàT PubSub can be used as a PEP service (PEP implementation not complete yet)
	- item publisher is enforced
	- categories handling (not complete)

v 0.1.1 (09/09/2014):
    bugfix release

v 0.1.0 (24/02/2014):
    ** FIRST PUBLIC RELEASE **