Issue #2330899 by attiks, Jelle_S, fietserwin: Allow image effects to change the MIME type + extension, add a convert image effect.
Issue #2298821 by LewisNyman: Move generic layout styling into system.admin.css.
Revert "Issue #2352857 by thamas: Fixed Improve the display of trigger icon (pencil)."

Needs more discussion.

This reverts commit b983fad1585b19378ed39b5fc4ccc40779bac733.
Issue #998898 by stefan.r, mradcliffe, Damien Tournoud, bzrudi71, Josh Waihi, chalet16, Stevel, chx: Fixed Make sure that the identifiers are not more the 63 characters on PostgreSQL.
Issue #2346027 by sqndr, ckrina, geodaniel: Fixed Unpublished content background overlaps tabs.
Issue #2352361 by ultimike: MigrateFieldTest @file docblock is wrong.
Issue #2348783 by larowlan, Cottser, kugta | skein: Fixed drupal_set_message inherits previous style if set to 'status'.