Add PHP 5.5 to the CI build matrix and switch to branch blacklisting.
Add PHP 5.5 to the CI build matrix and switch to branch blacklisting.

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