Fix #233, fix #268

then adjust to failure later if the request fails

skip ActionCable for follow/unfollow/block events, instead clear UI from
blocked account's posts instantly if block request succeeds. Add forgotten
i18n for sensitive content

created via remote look-up when domains differ but point to the same resource

This makes the UI appear less laggy. After all, the status *is* created
right there and then, it's the distribution to home timelines that can take
a while

all statuses/accounts to assemble, but at least lists don't have to be
re-rendered all the time now. Also add "mention" dropdown option

Also fix reloading of timelines after merge-type events

entire timelines (only fetch since last known ID). Side effect: account
timelines no longer update in real-time

Also upgrade react-redux to latest version. This is a performance update

Track relationship in redux state. Display follow/unfollow and following-back
information on account view (unstyled)