Uses dictionary update instead of iterating through keys.
Uses dictionary update instead of iterating through keys.

update_universe is a bottleneck on large data sets.

A large portion of that bottleneck is the call to getitem while
looping over the keys, so using update while passing along the internal
__dict__

Seeing about a 40% improvement.

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