xF2 Add-on Redis Cache By Xon 2.17.2

Features:

• Port Forum thread count caching from XF1 -> XF2 version of the add-on

Bugfixes:

• v1.x.y is XF1, so bump to v2.x.y
• Track latest credis
• Cleanup of phpdocs and random typing issues
• Workaround for Forum statistics always regenerating due to binary data being stored in a string (json_encode doesn't like this).

• Fix multi-fetch still using namespace mangling when saving was not. ie each pageload was forcing cache rebuilds by mistake.

• Switch to using json encode/decode for serialization, may not round-trip 100% correctly but by design.
  • As this add-on is used to cache potentially untrusted data, serialize/unserialize are strongly not recommended.
• Replace Doctrine Cache key mangling. The practice of injecting [ and ] into key names makes working with redis-cli annoying (most linux shells require [ or ] to be escaped in a confusing list of situations), and requires further escaping when using Redis KEYS or SCAN commands.