AccessManager does not invalidate changed items in AccessCache

Now that we are using authorization rules to access live and preview versions of a document respectively it has become necessary to invalidate the cached results of authorization checks in the AccessManager. We run into the following problems:

1.

• liveuser opens live document in site
• editor takes said live document offline by changing the availability property of the document
• liveuser can still see live document in site because result of read access check was cached

2.

• preview user opens preview document of which there is no preview variant and so sees live/preview document
• editor creates preview document by editing document (this sets original document's availability from live + preview to just live and new document's availability to preview)
• preview user continues to see the original variant of the document

Possible solution: instead of using the itemid for the cache key of the access cache, incorporate the modcount in the cache key of the access cache. Possibly we also need to incorporate the parent's modcount in the cache key because the with the node name facet it is the changing of the parent that counts (node names are stored in the bundle of the parent instead of on the item itself).