Remove Library Cruft

[chayim]

Currently redis-om-python makes use of libraries that need updating and/or removing. Examples include aioredis - now merged into redis, or six/types-six and types-redis.

[moznuy]

Hi @chayim, I've already mentioned this in #234 and #239. Could you look at them and answer some questions there?

[moznuy]

And related to aioredis, could you look at #233?