backend, pgsql storage: better items/notification handling, various fixes: - replaced const.VAL_AMODEL_ROSTER by const.VAL_AMODEL_PUBLISHER_ROSTER to follow change in pgsql schema - implemented whitelist access model - fixed bad access check during items retrieval (access was checked on recipient instead of requestor/sender) - getItemsData and notification filtering now use inline callbacks: this make these complexe workflows far mor easy to read, and clarity is imperative in these security critical sections. - publisher-roster access model now need to have only one owner, else it will fail. The idea is to use this model only when owner=publisher, else there is ambiguity on the roster to use to check access - replaced getNodeOwner by node.getOwners, as a node can have several owners - notifications filtering has been fixed in a similar way - psql: simplified withPEP method, pep_table argument is actually not needed - removed error.NotInRoster: error.Forbidden is used instead - notifications now notify all the owners, not only the first one

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 **