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

Issue #2217749 by Wim Leers, Jalandhar, visabhishek, damiankloip: Entity base class should provide standardized cache tags and built-in invalidation.

Issue #2185617 by Wim Leers, voidberg, drifter: Each page cache entry should have a theme cache tag.

Issue #2158003 by Wim Leers, msonnabaum, effulgentsia, moshe weitzman: Remove Block Cache API in favor of blocks returning #cache with cache tags.

Issue #2196807 by longwave, divesh.kumar: Convert all calls to check_plain() in core to Drupal\Component\Utility\String::checkPlain() in block module.

Issue #2171269 by effulgentsia, Wim Leers, InternetDevels, snig: Handle block rendering's #attributes correctly (fixes in-place editing of custom blocks).

Issue #2168333 by tim.plunkett, EclipseGc, yched, fago: Ensure custom EntityType controllers can be provided by modules.

Issue #1874498 by tim.plunkett, dawehner, jibran, benjy: Provide and use API methods for retrieving base plugin and derivative names from block plugin IDs.

Issue #1605290 by amateescu, msonnabaum, Caseledde, damiankloip, beejeebus, catch, Berdir, Wim Leers: Enable entity render caching with cache tag support.

Issue #1927608 by EclipseGc, tim.plunkett, effulgentsia: Remove the tight coupling between Block Plugins and Block Entities.

Issue #1591806 by tim.plunkett, ryanissamson, jenlampton, Risse, psynaptic, Gábor Hojtsy, kmcculloch, pakmanlh, Rob Loach: Change block 'subject' so that it's called (admin_)label like everything else on the theme layer.

Issue #1880588 by tim.plunkett, sun: Fixed Regression: invalid HTML in menu blocks due to _block_get_renderable_block() clobbering #theme_wrappers() of block contents.

Issue #1871696 by tim.plunkett, xjm, sun, msonnabaum, EclipseGc: Convert block instances to configuration entities to resolve architectural issues.