Issue #2946 by chx, michaellenahan, jcnventura, quietone, ifrik, wengerk, AaronBauman, salvis, pplantinga, sun, David_Rothstein, tatarbj, alexpott, Wim Leers, iMiksu, vijaycs85, anoopjohn, nedjo, Owen Barton, bjaspan, soxofaan, Gogowitsch, raman.b, robeano, deepakrmklm, bleen, xmacinfo, catch, beginner, dww, Gábor Hojtsy, webchick, Dries, larowlan, snufkin, RobRoy, bdragon, wizonesolutions, Lendude, sokru: Login fails and no warning is issued if cookies are not enabled

Issue #1987848 by disasm, ocsilalala, kim.pepper, pwieck, Cottser, pratik60, h3rj4n, pfrenssen, InternetDevels, ParisLiakos, rgoodine, tlyngej, vijaycs85, robeano: Convert system_theme_default() to a new style controller.

Issue #1987624 by disasm, robeano, piyuesh23, dawehner | vijaycs85: Convert batch_test() page callbacks to a new style controller.

Issue #1974492 by larowlan, jibran, disasm, tim-e, mdrummond, robeano, nick_schuch, wamilton, effulgentsia, tim.plunkett: Convert taxonomy_overview_terms() to a Form Controller.

- Patch #736298 by effulgentsia, eojthebrave, andypost, robeano: fixed Refactor file.module to use proper button click detection, enabling FAPI to improve button click detection security.