Background Updates: Pass back whether Group Writable support is being leveraged for an update to the WordPress.org API.
See #30245

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git-svn-id: http://core.svn.wordpress.org/trunk@30850 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: remove Genericons as a dependency from loading the main stylesheet.

Props iamtakashi, fixes #30532.
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git-svn-id: http://core.svn.wordpress.org/trunk@30855 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fourteen: remove Genericons as a dependency from loading the main stylesheet and IE-specific stylesheet. See #30532.
Built from https://develop.svn.wordpress.org/trunk@30866


git-svn-id: http://core.svn.wordpress.org/trunk@30856 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: remove license details for the image shown in the theme  screenshot file as it is Creative Commons Zero, which doesn't require attribution.

Props iamtakashi, fixes #30156.
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git-svn-id: http://core.svn.wordpress.org/trunk@30857 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Twelve: fix widget stacking problem in older IE browsers for Front Page template.

Props TomasM, hiwhatsup. Fixes #28938.
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git-svn-id: http://core.svn.wordpress.org/trunk@30858 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: minor updates to readme.txt file for clarity and removing non-ASCII characters. Closes #30675.
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git-svn-id: http://core.svn.wordpress.org/trunk@30859 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Customizer: Import missing `wp.customize.Control.prototype._toggleActive`.

Check also if `completeCallback` is set before calling it.

props westonruter.
see #30701.
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git-svn-id: http://core.svn.wordpress.org/trunk@30861 1a063a9b-81f0-0310-95a4-ce76da25c4cd