Uses ordered pip for Travis CI.
Uses ordered pip for Travis CI.

morrisonwudi/zipline,Scapogo/zipline,stkubr/zipline,dhruvparamhans/zipline,gwulfs/zipline,quantopian/zipline,MonoCloud/zipline,michaeljohnbennett/zipline,dkushner/zipline,grundgruen/zipline,CDSFinance/zipline,StratsOn/zipline,dmitriz/zipline,bartosh/zipline,MonoCloud/zipline,magne-max/zipline-ja,florentchandelier/zipline,StratsOn/zipline,umuzungu/zipline,euri10/zipline,enigmampc/catalyst,cmorgan/zipline,jimgoo/zipline-fork,bartosh/zipline,keir-rex/zipline,mattcaldwell/zipline,dhruvparamhans/zipline,erikness/AlephOne,ChinaQuants/zipline,DVegaCapital/zipline,joequant/zipline,grundgruen/zipline,chrjxj/zipline,erikness/AlephOne,alphaBenj/zipline,davidastephens/zipline,mattcaldwell/zipline,dkushner/zipline,jordancheah/zipline,wubr2000/zipline,magne-max/zipline-ja,sketchytechky/zipline,nborggren/zipline,iamkingmaker/zipline,gwulfs/zipline,YuepengGuo/zipline,CDSFinance/zipline,semio/zipline,florentchandelier/zipline,YuepengGuo/zipline,davidastephens/zipline,morrisonwudi/zipline,zhoulingjun/zipline,stkubr/zipline,aajtodd/zipline,wilsonkichoi/zipline,quantopian/zipline,iamkingmaker/zipline,otmaneJai/Zipline,kmather73/zipline,ronalcc/zipline,CarterBain/AlephNull,keir-rex/zipline,sketchytechky/zipline,AlirezaShahabi/zipline,CarterBain/AlephNull,joequant/zipline,nborggren/zipline,humdings/zipline,humdings/zipline,chrjxj/zipline,wubr2000/zipline,wilsonkichoi/zipline,Scapogo/zipline,semio/zipline,jimgoo/zipline-fork,enigmampc/catalyst,kmather73/zipline,jordancheah/zipline,cmorgan/zipline,dmitriz/zipline,umuzungu/zipline,michaeljohnbennett/zipline,alphaBenj/zipline,ronalcc/zipline,euri10/zipline,AlirezaShahabi/zipline,DVegaCapital/zipline,aajtodd/zipline,zhoulingjun/zipline,otmaneJai/Zipline,ChinaQuants/zipline