Issue #1424924 by Rob Loach: Added Use Composer for updating Symfony components (without removing Symfony code from repo).

- Patch #1260800 by David_Rothstein, lewisnyman, yoroy, nod_, thedavidmeister, effulgentsia: kill the overlay for widths below 640 pixels.

Issue #1658164 by Rob Loach, Berdir: Fixed TableSort Class not found exception thrown in database_test_theme_tablesort().

Issue #1619084 by kiamlaluno: Update documentation for drupal_render to reflect current function code

Issue #1552400 by mjonesdinero, SumeetSingh: Fix documentation for user_is_blocked, which was misleading.

Issue #1635084 by webflo, penyaskito, vasi1186, Berdir: Fixed Fatal error when deleting language due to DBTNG typo.

Issue #1085590 by Rob Loach, keichee, tim.plunkett, mfer, ericduran: Update jQuery UI to the latest in the git repository.

- Patch #1651270 by effulgentsia: remove IE8-specific workaround for lack of CSS3 box-shadow support.

- Patch #1645494 by effulgentsia: Allow core themes to display single-column on IE8: do not compensate for lack of media query support.

Issue #258785 follow-up by Gábor Hojtsy: Added CHANGELOG: Provide more flexible settings for initial language on content types.

Issue #1627208 by vasi1186, Gábor Hojtsy: CHANGELOG: Make language_list() and language_default() return instances of Language.

Issue #1333122 by effulgentsia, tim.plunkett: Clarify docs for theme and preprocess/process functions so it is clearer which ones get called for theme functions vs. templates