Adds dictionary style access to Position object.
Adds dictionary style access to Position object.

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