Merge pull request redis#623 from go-redis/feature/zlexcount

Add ZLexCount

Merge pull request redis#612 from okmeter/master

Stop ConnPool.tryDial for closed pool

Merge pull request redis#611 from go-redis/fix/pubsub-deadlock

Fix PubSub.Subscribe deadlock

Fix example

Merge pull request redis#594 from go-redis/feature/cluster-pubsub

Add PubSub support to Cluster client

Merge pull request redis#593 from go-redis/fix/pubsub-example

Fix PubSub example. Fixes redis#575

Merge pull request redis#588 from go-redis/fix/sentinel-reset-pool

Resent client pool when sentinel switches master

Merge pull request redis#580 from go-redis/fix/flush-db-async

Add FlushDBAsync and FlushAllAsync

Improve comment

Merge pull request redis#573 from go-redis/fix/no-error-on-empty-pipe…

…line

Don't return an error when pipeline is empty