Added tests for Predis\Commands\ZSetIncrementBy (ZINCRBY).
Added tests for Predis\Commands\ZSetIncrementBy (ZINCRBY).

RudyJessop/predis,quangnguyen90/predis,dzung2t/predis,CloudSide/predis,oswaldderiemaecker/predis,lvbaosong/predis,nguyenthaihan/predis,gencer/predis,channelgrabber/predis,WalterShe/predis,zhangyancoder/predis,RedisLabs/predis,mrkeng/predis,SwelenFrance/predis,vend/predis,SecureCloud-biz/predis,protomouse/predis,johnhelmuth/predis,dominics/predis,moria/predis,gopalindians/predis,stokes3452/predis,nrk/predis