Merge remote-tracking branch 'origin/master' into merge-upstream

Conflicts:
 	README.md
 	app/controllers/follower_accounts_controller.rb
 	app/controllers/following_accounts_controller.rb
 	app/serializers/rest/instance_serializer.rb
 	app/views/stream_entries/_simple_status.html.haml
 	config/locales/simple_form.ja.yml

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mastodon",
-  "license": "AGPL-3.0",
+  "license": "AGPL-3.0-or-later",
   "engines": {
     "node": ">=6"
   },