Plupload: Restore 3.8 handles and filenames to avoid breaking plugins.

fixes #27763.

Built from https://develop.svn.wordpress.org/trunk@28108


git-svn-id: http://core.svn.wordpress.org/trunk@27939 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Inline documentation for hooks in wp-includes/functions.php.

Props jesin, GaryJ.
Fixes #27715.

Built from https://develop.svn.wordpress.org/trunk@28109


git-svn-id: http://core.svn.wordpress.org/trunk@27940 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Plupload: restore the settings in media_upload_form(), see #27763
Built from https://develop.svn.wordpress.org/trunk@28110


git-svn-id: http://core.svn.wordpress.org/trunk@27941 1a063a9b-81f0-0310-95a4-ce76da25c4cd