Issue #2263351 by Wim Leers: Text Editor's in-place editing plugin broke in-place editing at large due to PHP fatal.
Issue #2257835 by tim.plunkett, sun, Jalandhar: Move form submission logic out of FormBuilder into a new class.
Issue #2261369 by Berdir: Introduce a common config entity base class for all bundle config entity types.
Issue #2249113 by tstoeckler, jessebeach: Use an entity save instead of db_insert() in user_install().
Issue #2229181 by pwolanin, Berdir, fago: MapItem::propertyDefinitions() claims it has a static value property, which is wrong.
!empty() is enough
Merge branch '8.x' into 2262863-image-srcset
ImageStyleInterface added
Merge branch '2262863-image-srcset' into 2260061-picture-polyfill-2