The Great Maintenance Update. No new features here. Instead, we've updated the build system to webpack 4, updated all our dependencies, and cleaned up a lot of linting issues.
* Changed: Remember which sections of the settings menu a user has expanded and restore that state when re-opening the menu.
* Changed: Begin tracking which settings a user has seen, so that a future update can begin highlighting newly added settings.
* Changed: Clean up the new localization code a bit more.
* Added: Custom timestamp formats for chat messages.
* Fixed: Hook the correct load event for video elements in rich link tool-tips.
* Fixed: Display Block and Hide Thumbnail buttons on the new game directory pages.
* Changed: Use markdown for rendering item descriptions in the settings menu rather than HTML.
* Update all usages of `tw-input` and `tw-select` to use the new, overly-verbose classes Twitch added.
* Add a few of the monkey faces to the local emote code to make them work.
* Override emotes when building the emote code <-> id map, to let emotes from higher sets override global emotes.
