* fix: fixed can not set redis maxIdle & maxActive when use redis session, fix for issue #236
* refactor: add StoreConfig.MaxIdle & StoreConfig.MaxActive set redis maxIdle & maxActive
* refactor: add redisutil.GetDefaultRedisClient to returns the RedisClient of specified address
* refactor: update redisutil.GetRedisClient returns the RedisClient of specified address & maxIdle & maxActive
* opt: set defaultMaxIdle=10, defaultMaxActive=50 when use default redis config
* How to set redis maxIdle & maxActive when use redis session:
~~~ go
sessionConf := session.NewDefaultRedisConfig("redis://xx.xx.xx.xx:6379/0")
sessionConf.BackupServerUrl = "redis://xx.xx.xx.xx:6379/0"
sessionConf.CookieName = "dotweb-example.SessionID"
sessionConf.MaxIdle = 20
sessionConf.MaxActive = 100
~~~
* 2020-12-19 21:00 at ShangHai