Add-ons Redis Cache By Xon 2.18.1

• Fix email rendering
• Prefix known global functions to avoid a current namespace lookup for the function.
• Work-around for non-desirable caching behaviour when CloudFlare (or similar) is forced to cache css.php output
  • If css.php would return empty output instead return a 404 and cache in redis for at most a second
  • Prevent polluting of caches if the time-stamp is in the future
• Improve XF Cloud support
  • config.php are not required if the stock Redis connector is used.
  • Currently XF Cloud does not use Redis for the main cache which prevents various redis-only add-ons from functioning as expected

• Force global namespace for functions which are known to be optimizable to bytecode in php
• Track latest upstream Credis library
• Fix "TypeError: Argument 1 passed to XXXX must be of the type YYYY, bool given" when the decompressor library for content stored in redis unexpectedly disappears

• Fix debug mode support for php 7.2 and earlier. Take 2