Issue #806982 by lokapujya, gnuget, miqmago, shashi1028, Floydm, bfroehle, kathyh, sreynen: Tables should take an optional footer variable and produce <tfoot>.
Issue #2223143 by damiankloip: Consolidate library extension caches into a single cache entry.
Issue #2279635 by thedavidmeister: Fixed template_preprocess_username() should use Unicode::truncate().