User: Invalidate `user_activation_key` on password update.
Query: Ensure that only a single post can be returned on date/time based queries.
Cache API: Ensure proper escaping around the stats method in the cache API.
Formatting: Expand `sanitize_file_name` to have better support for utf8 characters.
Brings the changes in [47633], [47634], [47635], [47637], and [47638] to the 4.7 branch.
Props: batmoo, ehti, nickdaugherty, peterwilsoncc, sergeybiryukov, sstoqnov, westi, westonruter, whyisjake, whyisjake, xknown.
git-svn-id: https://develop.svn.wordpress.org/branches/4.7@47650 602fd350-edb4-49c9-b593-d223f7449a82
f9be892b76