Updating Tender example to reflect latest modifications
Added description of delivery attributes to Item
Merge branch 'master' of github.com:openprocurement/openprocurement.api
Added authentication description
Updated tutorial to reflect change in modified property name (into dateModified)
Merge branch 'master' of github.com:openprocurement/openprocurement.api
Added description of 0.5 and 0.6 API releases