Merge branch '8.x' of git.drupal.org:project/drupal into 8.x

core/includes/ajax.inc

core/includes/common.inc

core/lib/Drupal/Core/Ajax/AjaxResponse.php

core/lib/Drupal/Core/CoreBundle.php

core/lib/Drupal/Core/Serialization/XmlEncoder.php

core/modules/block/lib/Drupal/block/Tests/BlockTest.php

...ules/edit/lib/Drupal/edit/Tests/MetadataGeneratorTest.php

...odules/editor/lib/Drupal/editor/Tests/EditorAdminTest.php

...ules/editor/lib/Drupal/editor/Tests/EditorLoadingTest.php

...ules/editor/lib/Drupal/editor/Tests/EditorManagerTest.php

core/modules/field_ui/field_ui.admin.inc

core/modules/file/file.module

core/modules/filter/config/filter.format.plain_text.yml

core/modules/filter/filter.admin.inc

core/modules/filter/filter.api.php

core/modules/filter/filter.install

core/modules/filter/filter.module

...ilter/lib/Drupal/filter/FilterFormatStorageController.php

...ter/lib/Drupal/filter/Plugin/Core/Entity/FilterFormat.php

.../modules/filter/lib/Drupal/filter/Tests/FilterAPITest.php