ref https://tc39.github.io/proposal-decorators/

* chore(yarn): Remove react-router

* chore(yarn): Remove react-router-scroll

* chore(yarn): Remove history

* chore(yarn): Add react-router-dom

* chore: Remove usages of react-router-scroll

* refactor: Upgrade to react-router-web

* refactor: Use fork of react-router-scroll

This reverts commit 2ddea9a6c8.

* fix: Issues mentions in the PR feedback

* Add semi to ESLint rules

* Add padded-blocks to ESLint rules

* Add comma-dangle to ESLint rules

* add config/webpack and storyboard

* add streaming/

* yarn test:lint -- --fix

Use ES Class Fields & Static Properties (currently stage 2) for improve class outlook.

Added babel-plugin-transform-class-properties as a Babel plugin.

* Replace browserify with webpack

* Add react-intl-translations-manager

* Do not minify in development, add offline-plugin for ServiceWorker background cache updates

* Adjust tests and dependencies

* Fix production deployments

* Fix tests

* More optimizations

* Improve travis cache for npm stuff

* Re-run travis

* Add back support for custom.scss as before

* Remove offline-plugin and babili

* Fix issue with Immutable.List().unshift(...values) not working as expected

* Make travis load schema instead of running all migrations in sequence

* Fix missing React import in WarningContainer. Optimize rendering performance by using ImmutablePureComponent instead of
React.PureComponent. ImmutablePureComponent uses Immutable.is() to compare props. Replace dynamic callback bindings in
<UI />

* Add react definitions to places that use JSX

* Add Procfile.dev for running rails, webpack and streaming API at the same time

* Makes username above toot box into a link.

* Prepends username above toot box with an @.

* fix(classnames): Status icon style classnames

Take out inline css and put into classnames for the following components: account, avatar, icon button, status action bar, notification.

* fix(status): Move styles from inline to classes for statuses

Move styles to classnames in components.scss for the following components:

display name
media gallery
status
status content
video player

* fix(classnames): Add classnames to rest of components

Take out inline styles and apply them to classnames in the sass for the following components:

button
column back button
slim column back button
collapsable column
dropdown menu
loading indicator
status list

* fix(classnames): Remove all non-dynamic inline styles

Components affected:

autosuggested
permalink
action bar
header
character counter
compose form
emoji dropdown
privacy dropdown
reply indicator
upload form
account auth
followers
getting started
column settings
mutes
settings
reblogs
status checkbox
report
action bar
status
card
boost modal
media modal
video modal

* fix(permalink): Do not lose classname

* fix(tests): Add space back in display name

* fix(status__wrapper): Remove duplicate css name

Remove incorrect style attribute. Remove style attribute all together. Cursor defaults to "auto" when not specified as 'default'.

* fix(nl): do not lose translations

* Remove deprecated features at React v15.5

- [x] React.PropTypes
- [x] react-addons-pure-render-mixin
- [x] react-addons-test-utils

* Uncommented out & Add browserify_rails options

* re-add react-addons-shallow

* Fix syntax error from resolve conflicts

* follow up 59a77923b3

* When avatar/header are GIF, generate static versions.
Account API returns "avatar"/"avatar_static", "header"/"header_static"
Static version is the same as original for other cases
Web UI de-animates avatars in toots, lists of users

Fix #441, fix #596, prerequisite for #1064

* Fix JS test

* Add rake task to generate static avatars/headers from GIF ones, add test

The "settings" links in the Getting Started section (or, if #399 were to happen, "more" menu) and compose sections are now different; the "compose" link is "Edit profile," while the one in the Getting Started section is now "Preferences."

All languages have been updated to accommodate this, based on the existing usages of these phrases in language files in the Rails part of the app!

addresses part of #384