Hide 'Database Upgrade Required' on admin/network/upgrade.php when you are not being asked to upgrade, to prevent confusion.

props duck_.
see #24845. see #23540.

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git-svn-id: http://core.svn.wordpress.org/trunk@25163 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix 'html5' theme support.
 * Require it to have a second argument when adding.
 * Merge, rather than replace, on second add.
 * Make current_theme_supports() work when two arguments are passed.

Adds unit tests.

props nathanrice for initial patch.
see #24932 for trunk.

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git-svn-id: http://core.svn.wordpress.org/trunk@25165 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove display of 'Previously restored by' in the revisions meta box as it is busted.

Fixes invalid markup (missing closing ul tag) when there was no previously restored revision.

see #25051 for trunk.

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git-svn-id: http://core.svn.wordpress.org/trunk@25166 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Nav menus: Allow assigning a new menu to an existing location when no theme setting is currently saved.

props ocean90.
see #25064, for trunk.

Built from https://develop.svn.wordpress.org/trunk@25195


git-svn-id: http://core.svn.wordpress.org/trunk@25167 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use get_nav_menu_locations() in wp_delete_nav_menu().

props nofearinc.
see #25064.

Built from https://develop.svn.wordpress.org/trunk@25196


git-svn-id: http://core.svn.wordpress.org/trunk@25168 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Case insensitivity for is_email_address_unsafe().

props jkudish.
fixes #25046.

Built from https://develop.svn.wordpress.org/trunk@25197


git-svn-id: http://core.svn.wordpress.org/trunk@25169 1a063a9b-81f0-0310-95a4-ce76da25c4cd