MAINT: Make TALib zipline_wrapper a module level function.
MAINT: Make TALib zipline_wrapper a module level function.

Prepare for making the zipline_wrapper operate on multiple sids,
as the needed nested logic will get cramped within the nested function.

Also, should help clearly define the inputs of the zipline_wrapper
function that are needed before it is passed to the BatchTransform
constructor.

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