These functions were used only by deleted upgrade steps
so it's safe to proceed with straight deletion, considering
them internal. Deletion has been documented in corresponding
upgrade.txt files:
- filter_mathjaxloader_upgrade_cdn_cloudflare()
- filter_mathjaxloader_upgrade_mathjaxconfig_equal()
This lets you programmatically prevent certain filters running on
certain content.
Also, I created some unit tests for the basic format_text functionality
since there did not seem to be any yet.
Instead we will create new MUC caches inside each filter plugin.
Please note that all cache filters should work with local caches
without the need of strict cache invalidation.
