Sylvia/docs/relnotes 7 30

@lamagnifica @mhoeber Please review. There's some back-and-forth about the PR with the Analytics changes in the Release HipChat room; I'll keep watching it and remove this info if necessary.
"include NEW post types" is what I think you meant. I would also rephrase put the emphasis on the fact that Question is the new type...right now it sounds like Discussion is new too, but it's not.