Throw notices when invalid date values are passed to WP_Date_Query.

`_doing_it_wrong()` notices are now generated when passing out-of-range values
(`month=13`) or invalid dates (`2014-02-29`).

Includes unit tests.

Props ChriCo.
Fixes #25834.
Built from https://develop.svn.wordpress.org/trunk@29925


git-svn-id: http://core.svn.wordpress.org/trunk@29677 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: Removes flashing of background behind fixed position elements when scrolling in mobile and desktop Safari.

Props iamtakashi, fixes #29973 and #29987.

Built from https://develop.svn.wordpress.org/trunk@29926


git-svn-id: http://core.svn.wordpress.org/trunk@29678 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: make sure we don't see borders through transparent linked images.

Props iamtakashi, fixes #29963.


Built from https://develop.svn.wordpress.org/trunk@29927


git-svn-id: http://core.svn.wordpress.org/trunk@29679 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: document the site-branding class in header.php.

Props NikV, fixes #29961.


Built from https://develop.svn.wordpress.org/trunk@29928


git-svn-id: http://core.svn.wordpress.org/trunk@29680 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Editor-expand:
- Better calculation for the caret position when auto-scrolling while typing.
- Fix auto-scrolling for non-WebKit browsers when the caret is above the top of the editor.
Fixes #29954
Built from https://develop.svn.wordpress.org/trunk@29929


git-svn-id: http://core.svn.wordpress.org/trunk@29681 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: readable comment details in the dark colour scheme.

Props NikV, fixes #29970.


Built from https://develop.svn.wordpress.org/trunk@29930


git-svn-id: http://core.svn.wordpress.org/trunk@29682 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove invalid `continue` calls from WP_Tax_Query::get_sql_for_clause().

This was leftover code from the previous implementation, which used a `foreach()`
loop. See [29901].

Props nofearinc.
See #29738, #29718.
Built from https://develop.svn.wordpress.org/trunk@29931


git-svn-id: http://core.svn.wordpress.org/trunk@29683 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add expectedIncorrectUsage flags for unit tests that generate invalid dates.

Since [29925], passing an invalid date to WP_Date_Query will generate a
_doing_it_wrong() notice. The current changeset adds the
`@expectedIncorrectUsage` flag to those existing unit tests that generate
invalid dates, such as those that test canonical redirect and is_404()
conditionals.

Fixes #25834.
Built from https://develop.svn.wordpress.org/trunk@29932


git-svn-id: http://core.svn.wordpress.org/trunk@29684 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use table aliases for columns in SQL generated by WP_Date_Query.

The use of non-aliased column names (eg 'post_date' instead of 'wp_posts.post_date')
in WP_Date_Query causes SQL notices and other failures when queries involve
table joins, such as date_query combined with tax_query or meta_query. This
changeset modifies WP_Date_Query::validate_column() to add the table alias when
it can be detected from the column name (ie, in the case of core columns).

A side effect of this change is that it is now possible to use WP_Date_Query
to build WHERE clauses across multiple tables, though there is currently no
core support for the automatic generation of the necessary JOIN clauses. See

Props ew_holmes, wonderboymusic, neoxx, Viper007Bond, boonebgorges.
Fixes #25775.
Built from https://develop.svn.wordpress.org/trunk@29933


git-svn-id: http://core.svn.wordpress.org/trunk@29685 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Support date_query by user_registered in WP_User_Query.

Props ChriCo, nacin.
Fixes #27283.
Built from https://develop.svn.wordpress.org/trunk@29934


git-svn-id: http://core.svn.wordpress.org/trunk@29686 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Comment/post author in/not_in for `WP_Comment_Query`.

Props nofearinc, chriscct7.
Fixes #29885.
Built from https://develop.svn.wordpress.org/trunk@29935


git-svn-id: http://core.svn.wordpress.org/trunk@29687 1a063a9b-81f0-0310-95a4-ce76da25c4cd