Port e18390cfe6 to glitch-soc

Port dfbadd6837 to glitch-soc

Port 023fe5181b to glitch-soc

- Move componentWillMount and componentWillReceiveProps logic to
  getDerivedStateFromProps.
- Compute CW auto-unfold status earlier

Port 9c38c5daa3 to glitch-soc

Port 795f0107d2 to glitch-soc

Media modals push an history state so that pressing back on mobile closes them.
We made sure to not scroll when opening them, but not when *closing* them,
which caused some issues in rare cases.

Port 478ca39e5e to glitch-soc

Port front-end changes from f7765acf9d to glitch-soc

Port 25b0d7538e to glitch-soc

Port front-end changes from c36b9cc5a6 to glitch-soc

Port front-end changes from c083816c24 to glitch-soc

If the current logged-in user is an admin, add quick links to the admin
interface in account and toot dropdown menu. Suggestion by @ashkitten

Port 248df68c36 to glitch-soc

Port 66dbb59aa1 to glitch-soc

Fixes #678

Port 025fbb8285 to glitch-soc

Port ac092d03e7 to glitch-soc

Port cdb101340a to glitch-soc,
but without dropping support for regexp filters yet.

Port bd0791d800 to glitch-soc

Port 2587fcdd27 to glitch-soc

Port d9b2f84c92 to glitch-soc

Port 904a2479dd to glitch-soc

Inspired from b6003afcdb but using component
properties instead of redux store for hidden/revealed state.

Port the video-player part of 036dd98abb to
glitch-soc. MediaGallery part ignored since it has diverged quite a bit.

This fixes #423

Unlike boosts and like, there is no confirmation dialog as misclicking
can be recovered without another user seeing it.

Port bf7757cbbc to glitch-soc