redis 6 and smaller fixes

• test against redis 6
• Lua json update (thanks @gsmith85)
• CLUSTER commands (thanks @kratisto)
• fix TOUCH
• fix a shutdown race conditionv

ZUNIONSTORE improvement

• ZUNIONSTORE now supports standard set types (thanks @wshirey)

TOUCH and custer commands

• support for TOUCH (thanks @cleroux)
• support for cluster and stream commands (thanks @kak-tus)

Lua concurrency

• make sure Lua code is executed concurrently
• add command GEORADIUSBYMEMBER, thanks to @kyeett

fixes for: lua, HSET, BLPOP

• globals protection for LUA code (thanks @vk-outreach)
• HSET update (thanks @carlgreen)
• fix BLPOP block on shutdown (thanks @Asalle)

basic streams, geodist, 128bit

• added XRANGE/XREVRANGE, XADD, and XLEN (thanks @skateinmars)
• added GEODIST
• improved precision for geohashes, closer to what real redis does
• use 128bit floats internally for INCRBYFLOAT and related (thanks @timnd)

Expose the Server

added Server(), to add custom commands

GEO

• added UNLINK
• fix DEL zero-argument case
• cleanup some direct access commands
• added GEOADD, GEOPOS, GEORADIUS, and GEORADIUS_RO

thanks for fixes!

bug fixes

• fix issue with ZRANGEBYLEX
• fix issue with BRPOPLPUSH and direct access

psubscribe, seed, redigo import

• proper import of github.com/gomodule/redigo
• fix messages generated by PSUBSCRIBE
• optional internal seed