* 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

* Disable toot button when above 500 characters

* Consider multibyte characters

* Consider spoiler_text

* Add eslint-plugin-jsx-a11y.

* Fix npm script.

* Adjust npm scripts so test also runs lint.

* Fix existing lint errors.

* Don't break on a11y issues.

* Add role and tabIndex.

* Add vim and Mac files to .gitignore and .dockerignore.

* Handle htmlFor (partially), a that's actually a button.

* Fix missing tabIndex.

* Add cursor:pointer to load-more

* Revert change to load_more.

* Fixes based on review.

* Update yarn.lock.

* Don't try to install fsevents on Linux (hides warning noise).

* jslint: remove trailing space

* jslint: fix no-nested-ternary issue

Follow the jslint [no-nested-ternary](http://eslint.org/docs/rules/no-nested-ternary)
rule. Rewritten ternary with if-then.

* Reorder javascript English locale file

 * Reorder translation string in order of the locale key.

* Add javascript English locale missing language keys

 * Search all javascript language keys by command:
   `grep -REho '<FormattedMessage .*\/>' ./app/assets/javascripts/.`

 * Add all the missing language keys and their values to `en.jsx`.

* Add javascript English locale missing language keys (2)

* Find all `defineMessages` calls with this command:
  `grep -Rl 'defineMessages({.*' ./app/assets/javascripts/.`

* Open all these files. Find the language key (`id`) in these
  statements.

* Add all the missing language keys and their values to `en.jsx`.

* Remove javascript English locale obsoleted language keys

 * Find all language keys that no longer exists in the source code
  and remove them. The removed keys include:

    * "compose_form.private"
    * "compose_form.unlisted"
    * "getting_started.about_addressing"
    * "getting_started.about_shortcuts"
    * "notification.mention"
    * "search.account"
    * "search.hashtag"
    * "tabs_bar.mentions"
    * "tabs_bar.public"

* Javascript English locale file add note

 * Add notes to contributors about the English translation files.
   Hope that will make translation process smoother.

* Update javascript locale defaultValue in code

 * Update the defaultValue in code according to the relevant
   translation in English locale file.

* Improve emoji picker look

* Add hover animation to emojis in picker

* 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

This patch stops disabling the toot text field when an image is uploading. Instead, you can type to your heart's content and when the image uploads it'll append the image URL, and restore the position of your cursor to wherever it was in the toot text just prior. Effectively, the image URL is appended to the toot, and typing is not interrupted at all! ✨

Descriptions of differences between scope are more clear

add ability to open status by URL from search (fix #53)

now allows to cycle through multiple images

"whole known network" which is what public timeline used to be

Only domain blocks with suspend severity will block PuSH subscriptions
Silenced accounts should not appear in conversations unless followed

I haven't had a chance to test this, because I don't currently have a fully functioning computer I can set up a dev-environment on, but this *should* make it so when a user toggles a post to be private, a disclaimer appears clarifying what "private" really means.

to only those from local users; Add link to "extended information" to
getting started in the UI; Add defaults for posting privacy; Change
how publish button looks depending on posting privacy chosen

sounds complex, but really it just reorganizes the posting options and
adds a seperator line

Federate spoiler_text using warning attribute on <content /> instead of a <category term="spoiler" />
Clean up schema file from accidental development migrations