MAINT: Use dateutil module for adding months to a datetime.
MAINT: Use dateutil module for adding months to a datetime.

Instead of having an advance_by_months function maintained in
Zipline, leverage the relativedelta module provided by dateutil.

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