Experimental support for Redis stream commands

[erulabs]

Hello!

I've added support for xread and xadd (generated the stub for xrange and xlen but haven't gotten to testing that yet) in a branch here: https://github.com/erulabs/thunk-redis/tree/erulabs/add-redis-stream-functions (diff: here)

I'll find the time to write a test or two hopefully - assuming this is on the right track! Didn't make a PR because, since these commands might change and don't exist in any released version of Redis, didn't seem appropriate! The new commands are discussed here: http://antirez.com/news/114

Thanks for your effort, love the driver!

[zensh]

Good work

[erulabs]

just wanted to update that i plan on adding the new group commands (http://antirez.com/news/116) to this branch and eventually making a PR once Redis5 comes out 👍 If someone wanted to beat me to it, that would be awesome, but I haven't forgotten 'bout this one!