Perfmatters v2.5.6

* Added new perfmatters_cdn_url filter along with new helper methods in the CDN class.
* Added the ability to completely disable Perfmatters code features using the new PERFMATTERS_DISABLE_CODE constant.
* Added confirmation message when turning on FastClick option.
* Added logic to remove the previous stored author ID when a code snippet is imported.
* Added host name to global settings and code snippet export files.
* Added additional logic to add an auto value to lazy loaded images sizes attributes when needed.
* Added separate used CSS generated files for different WooCommerce product types.
* Added dynamic request check in heartbeat function to prevent a possible PHP error.
* Updated lazy loading class to no longer add noscript tags by default for images and iframes to reduce HTML page size. The perfmatters_lazyload_noscript filter can still be used to turn that behavior back on.
* Updated get_atts_array utility method to use regex instead of wp_kses_hair for better compatibility.
* Reworked code snippet error handling class to work better with other exception handlers and existing error reporting.
* Turned off CSSLint in the code snippet editor, as it is outdated and was leading to false positives.
* Adjusted gutter column layout in the code snippet editor to be more consistent between different code types.
* Adjusted code snippet priority field to allow both negative and zero input values.
* Fixed an issue where CSS code snippets set to run in the footer were not having their conditions checked.
* Fixed an issue where CSS code snippets were not always printing where expected based on the set location and priority.
* Fixed an issue with certain code snippet input fields not being escaped properly in the UI leading to a broken layout in some cases.
* Fixed an issue where YouTube iframes rendered with a preview thumbnail that had autoplay forced off in their query string would require a double click.
* Fixed an issue where the referrerpolicy iframe attribute did not get applied to the generated iframe when using YouTube preview thumbnails.
* Translation updates.