Issue #1204784 by bdgreen, Kevin Morse, valthebald, kiamlaluno, droplet: Fix code comment in drupal_retrieve_form

Issue #799356 by vijaycs85, m1n0, jaffaralia, effulgentsia: Fixed _form_set_class() is too aggressive in assigning the 'error' class.

Issue #1888454 by kiamlaluno: Remove irrelevant information from form_process_vertical_tabs() documentation

Issue #1785436 by Boobaa: Fixed Submission of #required elements without #title and empty value does not display any error.

Issue #1414510 by andypost, Spleshka, perelman.yuval, tim.plunkett: Fixed Remove drupal_reset_static() for drupal_html_id() when form validation fails.

Revert "Issue #1742438 by larowlan, Christian Biggins, kim.pepper, dcam, Everett Zufelt, mgifford: Fixed Vertical tabs header and container rendered even when no vertical tabs."

Concerns raised in http://drupal.org/node/1742438#comment-6609888 that this breaks backwards compatibility.

This reverts commit d462cafd.

Issue #1742438 by larowlan, Christian Biggins, kim.pepper, dcam, Everett Zufelt, mgifford: Fixed Vertical tabs header and container rendered even when no vertical tabs.

Issue #699604 by cam8001, nmudgal: Use file name for links to form API reference instead of full URL

Issue #171267 by tim.plunkett, chx, NROTC_Webmaster, dcam: Fixed form redirects removes get variables like sort and order.

Issue #635046 by claudiu.cristea, sun, fago: Fixed form_state_values_clean() is polluting form values.

Issue #811542 by David_Rothstein, attiks, thekevinday, effulgentsia, chx: Fixed Regression: Optional radio buttons with an empty, non-NULL default value led to an illegal choice error when none were selected.

Issue #1591726 by sun, tim.plunkett: Fixed Missing form_id, form_build_id, and form_token when using custom #parents and #tree = TRUE on $form itself.

Issue #1421410 by andypost, Niklas Fiekas: Fixed  not defined in form_pre_render_conditional_form_element().

Revert "Issue #1475666 by filijonka, Niklas Fiekas, Devin Carlson, Kevin Morse, tstoeckler: Fixed PHP error because of typo in form.inc line 3025."

This reverts commit ea8e74bb.

Issue #1475666 by filijonka, Niklas Fiekas, Devin Carlson, Kevin Morse, tstoeckler: Fixed PHP error because of typo in form.inc line 3025.

Issue #811542 by bojanz, sun, mlncn, chx, pillarsdotnet, loganfsmyth, xjm: Fixed Regression: Required radios throw illegal choice error when none selected.

Issue #381994 by xjm, good_man, elcuco, brianV, yhager: Fixed Machine-name fields are always in Latin characters, and should therefore always be LTR.

Issue #866292 by marcingy, ygerasimov, quicksketch, attiks, furamag: Fixed '0' not displayed as checkbox / radios options (nor as any element #title).

- Patch #1229868 by nicl, DjebbZ: hook_form_BASE_FORM_ID_alter(), hook_form_alter(), and hook_form_FORM_ID_alter() doc inconsistent.