Plupload wrapper: Call init callback on PostInit event.
Fixes the background image uploader in Customizer, which was broken after [27316].

fixes #27620.

git-svn-id: https://develop.svn.wordpress.org/trunk@27933 602fd350-edb4-49c9-b593-d223f7449a82
TinyMCE: improve setting disabled/enabled/activated states on the Unlink button, fixes #27309

git-svn-id: https://develop.svn.wordpress.org/trunk@27934 602fd350-edb4-49c9-b593-d223f7449a82
Database: Fall back from ext/mysqli to ext/mysql if the connection fails.

This allows us to avoid breaking a site that works under ext/mysql but is misconfigured for ext/mysqli.

props pento.
see #21663.


git-svn-id: https://develop.svn.wordpress.org/trunk@27935 602fd350-edb4-49c9-b593-d223f7449a82
Themes: Hide 'Add New' with no JS. see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@27936 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Fix sorting, counts, keyboard navigation; add prev/next to previews.

props matveb.
see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@27937 602fd350-edb4-49c9-b593-d223f7449a82
Fix typo in verify_file_md5() description. see [25541].

props siobhan.
see #27651.

git-svn-id: https://develop.svn.wordpress.org/trunk@27938 602fd350-edb4-49c9-b593-d223f7449a82
Clarify tooltips on Edit Image screen.

props siobhan.
fixes #27651.

git-svn-id: https://develop.svn.wordpress.org/trunk@27939 602fd350-edb4-49c9-b593-d223f7449a82
Theme Installer: Center spinner, remove plural string.

fixes #27581. see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@27940 602fd350-edb4-49c9-b593-d223f7449a82
TinyMCE: better calculation for editor height when switching Text to Visual and back. Add stopping of editor resizing when the mouse leaves the browser window. See #27279

git-svn-id: https://develop.svn.wordpress.org/trunk@27941 602fd350-edb4-49c9-b593-d223f7449a82
Edit image modal:
- Make the calculation of the aspect ratio more robust.
- Better getting of the image height and width.
Props gcorne, see #27366

git-svn-id: https://develop.svn.wordpress.org/trunk@27942 602fd350-edb4-49c9-b593-d223f7449a82
Remove a blank line and @global reference in the PHPDoc for `comment_author_email_link()`.

Props norcross, ocean90.
Fixes #27655.


git-svn-id: https://develop.svn.wordpress.org/trunk@27943 602fd350-edb4-49c9-b593-d223f7449a82
TinyMCE: add image backgrounds for more and nextpage tags (also jshint fix for theme.js). Fixes #27106

git-svn-id: https://develop.svn.wordpress.org/trunk@27944 602fd350-edb4-49c9-b593-d223f7449a82
Add missing space between strings.

props rachelbaker.
fixes #27597.


git-svn-id: https://develop.svn.wordpress.org/trunk@27945 602fd350-edb4-49c9-b593-d223f7449a82
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
Merge branch 'master' into a11y-ui-improvements

Conflicts:
	src/wp-admin/css/customize-controls.css
	src/wp-includes/class-wp-customize-control.php
	src/wp-includes/js/customize-views.js