* Refactor shouldUpdateScroll passing

So far, shouldUpdateScroll has been manually passed down from the very top of
the React component hierarchy even though it is a static function common to
all ScrollContainer instances, so replaced that with a custom class extending
ScrollContainer.

* Generalize “press back to close modal” to any modal and to public pages

* Fix boost confirmation modal closing media modal

Fix #15280

Also adds the new action bar and blurhash-based background
color to audio and video modals

* Fix audio and video items in account gallery in web UI

- Fix audio items not using thumbnails
- Fix video items not using custom thumbnails
- Fix video items autoplaying like GIFs

* Change audio and video items in account gallery to autoplay when opened in web UI

* Fix code style issue

Fix video attachments having a GIF label in media tab in web UI

* Add "view context" button to media modal when opened from gallery

* Add "view context" button to video modal

Allow closing the video modal by navigating back in the browser,
just like the media modal

* Add blurhash

* Use fallback color for spoiler when blurhash missing

* Federate the blurhash and accept it as long as it's at most 5x5

* Display unknown media attachments as blurhash placeholders

* Improve style of embed actions and spoiler button

* Change blurhash resolution from 3x3 to 4x4

* Improve dependency definitions

* Fix code style issues

* Improved media modal

ImageLoader: Impliment pinch zoom by CSS `transform: scale(X)`
ImageLoader: Impliment panning by CSS `overflow: scroll`
ImageLoader: Larger image
MediaModal: Larger close button
MediaModal: Close the modal by swiping vertically
MediaModal: Show/hide close button and right/left navigation on tapping image
MediaModal: Change the `pointer-event` CSS prpp to get more blank space to close the modal
ImageLoader: Zoom/reset zoom on double tap
MediaModal: disable vertical swiping while horizontally swiped
ImageLoader: prevent propagating touchmove event to MediaModal
MediaModal: Adjust size and potision of buttons
ImageLoader: Adjust scroll potision on pinch zoom

* Remove "swipe to close" and "double tap to zoom" features

* remove unused prop and functions

removed `onScroll` prop and `handleScroll` func in ImageLoader

* separate zoom functionary to ZoomableImage component

adjust styling of ImageLoader
add styling for ZoomableImage

* adjust size and potision of close button of media modal

* Fix for gif video

add `onClick` prop to ExtendedVideoPlayer
specify `onClick` prop to video tag for switching nav of `MediaModal`
add `.video-modal` class to scss to separate styling for `VideoModal`

* fix styling for centering

specify height of `ZoomableImage` by pixel
clean styling for `ImageLoader`

* fix lint errors

* small fix

* fixed designated parts

* Fix #117 - Add ability to specify alternative text for media attachments

- POST /api/v1/media accepts `description` straight away
- PUT /api/v1/media/:id to update `description` (only for unattached ones)
- Serialized as `name` of Document object in ActivityPub
- Uploads form adjusted for better performance and description input

* Add tests

* Change undo button blend mode to difference

* Redesign video player

* Use new video player on static public pages too

* Use media gallery component on static public pages too

* Pause video when hiding it

* Full-screen sizing on WebKit

* Add aria labels to video player buttons

* Display link card on public status page

* Fix fullscreen from modal sizing issue

* Remove contain: strict property to fix fullscreen from columns

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

* Add react/no-string-refs ESLint rule

* Add react/jsx-boolean-value ESLint rule

* Add react/jsx-closing-bracket-location ESLint rule

* Add react/jsx-indent ESLint rule

* Add react/jsx-curly-spacing ESLint rule

* Add react/jsx-equals-spacing ESLint rule

* Add react/jsx-first-prop-new-line ESLint rule

* Add react/jsx-no-duplicate-props ESLint rule

* Add react/jsx-tag-spacing ESLint rule

* 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

* 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