Notify administrators of successful, failed, and pending core updates.

Blocks future background updates after critical failures, but allow retries in certain situations. More in the ticket.

fixes #10787.

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git-svn-id: http://core.svn.wordpress.org/trunk@25753 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use full paths to images so they work on wp-admin/network/about.php and user/about.php. see #25603.

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git-svn-id: http://core.svn.wordpress.org/trunk@25754 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use correct variable. fixes #10787.

Built from https://develop.svn.wordpress.org/trunk@25843


git-svn-id: http://core.svn.wordpress.org/trunk@25755 1a063a9b-81f0-0310-95a4-ce76da25c4cd
CSS cleanup for the about page.

Also fixes for IE and support for RTL.

see #25603.
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git-svn-id: http://core.svn.wordpress.org/trunk@25756 1a063a9b-81f0-0310-95a4-ce76da25c4cd
About page: Use box-sizing: border-box on the password meter so pixels line up.

Also eliminates a duplicate width: 100% property.

fixes #25603.

Built from https://develop.svn.wordpress.org/trunk@25845


git-svn-id: http://core.svn.wordpress.org/trunk@25757 1a063a9b-81f0-0310-95a4-ce76da25c4cd
IE7: Fix width of the password input field on the about page. see #25603.
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git-svn-id: http://core.svn.wordpress.org/trunk@25758 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Since we're dealing with a huge password meter, don't bold half of the result strings unnecessarily. see #25603.

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git-svn-id: http://core.svn.wordpress.org/trunk@25759 1a063a9b-81f0-0310-95a4-ce76da25c4cd