#152 sensitive items in ferret results

[Bob Firth]

All of the new search capabilities depend on searching the ferret index instead of the database itself. This means that we can't block sensitive things using the same approach that we have used elsewhere.

We need to revamp our system for dealing with sensitive items (such as sorrow) so that it can integrate with this method of searching.

It seems like the best approach for now would be to test whether or not an entity should be displayed in the search results page, and put a block on anything which is not accessible to the user within the view (as opposed to not returning a result at all, or eliminating the results in the controller).

This would mean that sensitive items could be listed in a different way (e.g. the black thumbnail) or simply passed over, depending on what we think is best.