1. Fix#12 - return number of added items for non-increment usecase.
2. Fix#15 - fix double precision response. I use a different printing algorithm that of Redis
therefore there could be string differences between 2 systems. However, both replies should
be equivalent numerically.
3. Fix#13. Reject ZADD with LT and GT options together.
4. Fix#11 - return correct error when parsing invalid scores.
1. Remove CO::STALE modifier since it's not relevant for now.
2. Propertly wire CallFromScript function to be called from redis.call.
3. Define 3rd party lua dependency as part of dragonfly project.
4. Add ARGV/KEYS arrays to lua scripts
Files are taken from redis commit e84ccc3f566f78344b098c3eef6e371653bc311b
We need low-level redis datastructures for encoding values that are not strings,
i.e. lists, sets, zsets etc.
