Issue #1216978 by cosmicdreams, jyve, mortendk, jessebeach, Jacine, aspilicious: Clean up CSS for Contextual module

Issue #1388496 by barraponto: Fixed Default field.tpl.php prints a clearfix class theme_field() doesn't.

Issue #681760 by agentrickard, Josh Waihi, et al: eliminate duplicates caused by node_access() table joins.

- Patch #1222106 by Gábor Hojtsy, plach, xjm: Unify language negotiation APIs, declutter terminology.

- Patch #1272840 by attiks, Gábor Hojtsy, pp, Dave Reid, catch: upgrade path for language domains and validation.

- Patch #1454538 by effulgentsia, Gábor Hojtsy, kalman.hosszu: langcode property to all entity types; for the user entity, distinguish entity language from user's language preference.

Issue #1393604 by tedbow, Niklas Fiekas: Fixed path_form_element_validate() does not send correct  parameter to form_set_error().

Issue #1347134 by c31ck, amateescu, Shyamala, DamienMcKenna: Fixed 'View voting results' permission is misleading.

Issue #1058564 by Niklas Fiekas, droplet, grendzy, dixon_, naxoc: Fixed User picture does not appear in comment preview.

Issue #746240 by c960657, Gábor Hojtsy: Fixed Race condition in locale() - duplicates in {locales_source()}.

Issue #97327 by PMunn, NROTC_Webmaster, haydeniv, maartenvg, xjm, killes@www.drop.org, gdavid, Zed Pobre: Fixed Data corruption in comment IDs (results in broken threading on PostgreSQL).

Issue #1451032 by NROTC_Webmaster: Add note to schema docs about varchar columns needing to have length specified

Issue #1369332 by Damien Tournoud, basic, sun, no_commit_credit: Fixed Avoid deadlock issues on the {node} table.

Issue #1366854 by quicksketch: Added Pass #size attribute to the child upload field in the managed_file() element.

Issue #1315992 by xjm: Remove path designations from menu callback docs to conform with current 8.x standards