Allow user_id to be an array of IDs in WP_Comment_Query.

props mordauk.
fixes #27064.

Built from https://develop.svn.wordpress.org/trunk@27258


git-svn-id: http://core.svn.wordpress.org/trunk@27115 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Allow current_time() to accept a date format string, adding to 'timestamp' and 'mysql'.

props danielbachhuber.
fixes #21653.

Built from https://develop.svn.wordpress.org/trunk@27259


git-svn-id: http://core.svn.wordpress.org/trunk@27116 1a063a9b-81f0-0310-95a4-ce76da25c4cd