Issue #1954892 by dawehner, tim.plunkett, David_Rothstein, effulgentsia: Replace 'theme callback' and hook_custom_theme() with a clean theme negotiation system.

Issue #2118703 by Wim Leers, amateescu: Introduce #post_render_cache callback to allow for personalization without breaking the render cache.

Issue #2057259 by alexpott, cweagans, swentel: Fixed Malformed modulename.info.yml file causes fatal error.

Issue #2113015 by Wim Leers, amateescu: Add drupal_merge_attached() function, to merge #attached assets.

Issue #2089327 by thedavidmeister, Cyberschorsch: Remove / deprecate calls to drupal_strip_dangerous_protocols() use \Drupal\Component\Utility\Url::stripDangerousProtocols().

Issue #2089351 by thedavidmeister, meba: Convert all calls to check_plain() in core to Drupal\Component\Utility\String::checkPlain() in core/includes.

Issue #2049207 by dlu, blakehall, janstoeckler, ramlev, Moderate | Cottser: Replace .tpl.php with .html.twig in documentation.

Issue #2100329 by cosmicdreams: Use \Drupal instead of Drupal to make IDEs and static code analyse tools happy.

Issue #1798738 by alexpott, mtift, tayzlor, ianmthomasuk, Albert Volkman, heyrocker, cam8001: Move css_js_query_string() to state system.

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

Issue #1793648 by nod_, kmox83, droplet, rteijeiro: Follow-up: replace all occurence of Drupal.settings with drupalSettings.

Issue #1827112 by alexpott, vijaycs85, dawehner, cspitzlay, cam8001: Convert 'install_profile()' variable to Settings.

Issue #2047619 by dawehner, pwolanin, tstoeckler, thedavidmeister: Add a link generator service for route-based links.

Issue #2057155 by pwolanin, dawehner: Add a generateFromRoute() method on the url generator to accept options like url().

Stupid commit message. :P Fixing. :P

This reverts commit 838bf21e.

Issue #2068217 by thedavidmeister: Fixed array('hook') syntax for suggestions is broken for #theme_wrappers().

Issue #2032535 by dawehner, katbailey, pwolanin, Crell: Resolve 'title/title callback' by adding a _title propery on the route and allow a title be part of the render array.

Issue #1957142 follow-up by dawehner, jibran: Fix a few more config() => Drupal::config() stragglers.

Issue #1476810 by Spleshka, franz: Fixed drupal_serve_page_from_cache() can serve uncompressed data with Content-Encoding gzip header with page_cache_without_database = 1.

Issue #1164682 by mgifford, thedavidmeister, good_man, mvc, clemens.tolboom, sxnc, lazysoundsystem: Fixed links with a known language need language identifier.

Issue #1941288 by larowlan, effulgentsia, dawehner, nod_: Fixed Regression: ajaxPageState not being updated with AjaxResponse, assets (js/css) being added twice.

Issue #1855260 by beejeebus, msonnabaum, larowlan: Fixed Page caching broken by accept header-based routing.

Issue #2028499 by tsphethean, damiankloip, dawehner: Drupal_sort_weight() should be converted to a class.

Issue #2042285 by thedavidmeister, jenlampton, Mark Carver: #theme_wrappers() should be able to have a unique set of variables per wrapper hook.