* add the apcu caching ability for performance
When the PHP extension APCu is loaded, the settings class and the auto_loader will cache their results across requests in RAM. For more information about the APCu extension visit the PHP page: https://www.php.net/apcu
* use global instead of default terminology
* Build an array in the auto_loader constructor
* Update auto_loader.php
* Update auto_loader.php
* minor adjustment to name and comment and remove trailing closing tag
* use best practices for the loader method
Allowing the loader method:
- Should Never Be Called Manually
- Prevents External Modification
- Hides Implementation Details
* cache array in the temp folder and load if available
* re-organize functions within the class
* add cache recreation for auto_loader in upgrade_menu
* add cache recreation for auto_loader in upgrade_menu
* Update app_languages.php