Support ALL options of the Redis driver in Redis configuration

This pr basically solves the problem in #1252. It allows support for all options of the redis driver during redis client configuration.
For unix socket you can now do ``redis = Sidekiq::RedisConnection.create(:path => '/var/run/redis.sock', :db => 8)`` . Basically, you can pass any option you would pass to the official ruby redis driver.
Thanks