Overlay: Use hexadecimal character reference

Replace multiplication sign character (×) with hexadecimal character reference (&#xd7;). Fixes incorrect display of close character in mobile menus when using different character encodings. Without the fix, the 'x' is only displayed correctly when using utf-8 character encoding.
Multimedia plugin: Remove duplicate code

Multimedia plugin - remove duplicate code for case "setPreviousTime."
Merge pull request #4958 from m14e/v4.0

Overlay: Use hexadecimal character reference