DH DG; don't display blocked people in stream; switch controls in stream; disallow blocking yourself

DH DG; made privacy page; can now unblock a user; users are actually being blockocked in ajaxed streams

exclude blocked users from all streams

fixed scoping stuff

Issue 2298 following dot tags

Following a hashtag with a dot now no longer breaks the user's stream page.
All unacceptable hashtag chars are stripped out, and the given tag is
normalized before being followed.

Retry federation if remote pod is down

Issue 2213 hashtag markdown em collision

Issue 2264 fix tag parsing