Header images: Handle cropping failures.

props ehg.
see #21785.


git-svn-id: https://develop.svn.wordpress.org/trunk@27946 602fd350-edb4-49c9-b593-d223f7449a82
Header images: Accessibility and style improvements. Headers no longer jump around when chosen.

props mcsf, ehg.
see #21785.


git-svn-id: https://develop.svn.wordpress.org/trunk@27947 602fd350-edb4-49c9-b593-d223f7449a82
Edit image modal: check if full size exists before trying to use it for setting aspect ratio, props gcorne, see #27366

git-svn-id: https://develop.svn.wordpress.org/trunk@27948 602fd350-edb4-49c9-b593-d223f7449a82
TinyMCE: update the default style for html5-captions, props obenland fixes #26642

git-svn-id: https://develop.svn.wordpress.org/trunk@27949 602fd350-edb4-49c9-b593-d223f7449a82
Throw a user notice when the editor ID used for TinyMCE contains brackets, props nacin, fixes #27601 

git-svn-id: https://develop.svn.wordpress.org/trunk@27950 602fd350-edb4-49c9-b593-d223f7449a82
When autosaving a new post for the first time after a title was typed, cancel the autosave if the user is submitting the form. (Includes a precommit fix for customize-controls.css.) Props Nessworthy, davidmarichal, fixes #27657

git-svn-id: https://develop.svn.wordpress.org/trunk@27951 602fd350-edb4-49c9-b593-d223f7449a82
Fix a typo in the PHPDoc description for the `WP_Http_Curl->max_body_length` property.

Props eightface.
Fixes #27681.


git-svn-id: https://develop.svn.wordpress.org/trunk@27952 602fd350-edb4-49c9-b593-d223f7449a82
Avoid an undefined index notice in wp_http_validate_url().

props jesin.
fixes #27684.

git-svn-id: https://develop.svn.wordpress.org/trunk@27953 602fd350-edb4-49c9-b593-d223f7449a82
Customizer: Add `height: auto;` for `select[multiple]`.

fixes #27662.

git-svn-id: https://develop.svn.wordpress.org/trunk@27954 602fd350-edb4-49c9-b593-d223f7449a82
Fix typo in hook description for `async_upload_{$type}`.

git-svn-id: https://develop.svn.wordpress.org/trunk@27955 602fd350-edb4-49c9-b593-d223f7449a82
RTL: Fix taxonomy quick edit list alignment.

props SergeyBiryukov.
fixes #27629.


git-svn-id: https://develop.svn.wordpress.org/trunk@27956 602fd350-edb4-49c9-b593-d223f7449a82
Don't pass variables by reference.

props markjaquith.
fixes #27656.


git-svn-id: https://develop.svn.wordpress.org/trunk@27957 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Fix displaying of errors.

props SergeyBiryukov.
fixes #27640.


git-svn-id: https://develop.svn.wordpress.org/trunk@27958 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Better responsive styles for feature filters.

props matveb.
fixes #27661.


git-svn-id: https://develop.svn.wordpress.org/trunk@27959 602fd350-edb4-49c9-b593-d223f7449a82
Revert the changes made to `data.title` in playlist Underscore templates in [27869]. `{{ data.title }}` causes the title to be double-encoded on the front end.

See #27574.



git-svn-id: https://develop.svn.wordpress.org/trunk@27960 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Use JSONP for api.wordpress.org requests.

fixes #27639.


git-svn-id: https://develop.svn.wordpress.org/trunk@27961 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Don't encode description entities/HTML.

props johnbillion.
fixes #27641.


git-svn-id: https://develop.svn.wordpress.org/trunk@27962 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Separate API from an event handler to avoid issues where a false return value stops the event.

see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@27963 602fd350-edb4-49c9-b593-d223f7449a82
Better checks for contributors when saving posts.

props dd32, kovshenin, plocha.
see #27452.


git-svn-id: https://develop.svn.wordpress.org/trunk@27964 602fd350-edb4-49c9-b593-d223f7449a82
Inline documentation for remaining hooks in wp-admin/includes/upgrade.php.

Props jackreichert, vancoder.
Fixes #27646.


git-svn-id: https://develop.svn.wordpress.org/trunk@27965 602fd350-edb4-49c9-b593-d223f7449a82