Add mini test suite. First for autoclean.
Mark this version as compatible with redis.py up to 2.6.x
Make compatible with redis.py ~2.7-2.10.

Strangely the rename function threw errors when the first key did
not exists. The most minimal change I could think of was replacing
them with custom Lua rename scripts that just don't care for existing
keys. There is probably a better non-script solution but that would
require (major) changes to the core logic of autoclean.
Release 2.0.0 - compatibility with redis.py 2.7.6 upwards.