Issue #2379683 by Gábor Hojtsy: Fix configuration schema issues in contact (indirectly user and system) modules
Issue #2380573 by tibbsa: Add @return $this to ConfigInstallerInterface::setSynching
Issue #2030661 by lokeoke, lokapujya, larowlan, dinarcon, daffie, izus, Ivan Zugec: Expand Tour with methods
Issue #1224892 by iaine, lapistano, LinL, jonvk: Duplicate code in mysql/schema.inc (createKeySql = createKeysSqlHelper)
Issue #2350723 by rjacobs: State toggles for Enable alt/title and Require alt/title not functioning