Issue #2350837 by dawehner, Berdir, larowlan, Wim Leers: Convert most usages of EntityInterface::getSystemPath() to use routes

Issue #2328111 by dawehner, martin107, neclimdul: Replace most instances of the DRUPAL_ROOT constant with the app.root container parameter.

Issue #2312093 by alexpott, yched, andypost, swentel | xjm: Rename FieldInstanceConfig to FieldConfig.

Issue #999338 by lauriii, joelpittet, Sir-Arturio, mgifford, mlncn, alarcombe, sun | Eric_A: Fixed theme_image() alt attribute cannot be passed in $variables['attributes'] .

Issue #2287727 by yched, swentel, alexpott: Rename Field[instance]Config classes and entity types (again).

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2143291 by plach, alexpott, xjm, effulgentsia, pwolanin, swentel | yched: Clarify handling of field translatability.

Issue #2099131 by jessebeach, Wim Leers, catch, Berdir, benjifisher, martin107, andypost: Use #pre_render pattern for entity render caching.

Issue #1939068 by joelpittet, tlattimore, Cottser, chrisjlee, rteijeiro, mdrummond, drupalninja99, jenlampton, shanethehat, InternetDevels, DamienMcKenna, gavin.hughes, carsonevans, ezeedub: Convert theme_image() to Twig.

Issue #2095303 by swentel, plopesc, Berdir, claudiu.cristea, yched: Rename 'field_entity' to 'field_config' and 'field_instance' to 'field_instance_config'.

Issue #2042773 by yched, Berdir, pcambra: Change #items within a theme_field() render array from an *array* to the same $items *object* used throughout the rest of the formatter pipeline.

Issue #2080393 by mrsinguyen: Remove Unused local variable  from /core/modules/image/lib/Drupal/image/Tests/ImageThemeFunctionTest.php.

Issue #2010126 follow-up by Eric_A: Replace theme() with drupal_render() in image module for theme_image_formatter().

Issue #1782244 by heyrocker, andypost, tstoeckler: Convert image styles  array into ImageStyle (extends ConfigEntity).

Issue #606598 by andypost, stBorchert, sun, aspilicious, joachim: Added Human readable image-style names.

Issue #1175764 by tim.plunkett, Rob Loach, eojthebrave: Added Have theme('image_style()') inject the style name as a class.

Issue #1711070 by kid_icarus, tim.plunkett, xjm, droplet, zendoodles and cam8001: Convert tests to use ::$modules property instead of parent::setUp($modules).

Issue #1038932 by tim.plunkett, Chris Gillis: Theme_image_formatter() assumes that title, alt, and options are always set.