Multiple id request for FaciaPress

This is basically #6485 with better memcaching. I had to force update as I lost one commit, and that is the reason for the new PR.

@robertberry @gklopper @stephanfowler 
If I were extremely anal I would point out that `map` here ought to be `foreach` as you're doing it for the side effect not the value of the expression. But I'm not so I won't. :wink: