* Improvement: Load jQuery UI files locally, thus removing any unnecessary dependency on another site (e.g. not from "ajax.googleapis.com")
* Improvement: Escape as late as possible all variables when echoed
* Improvement: Replaced json_encode() with wp_json_encode() for better security
* Fix: When a word containing "calc" (e.g. calculation) was included in CSS comments, sometimes, the code following the comment was stripped