Fix GitbookIO/gitbook.io#69: copy cover files at multi-langs root
Fix GitbookIO/gitbook.io#69: copy cover files at multi-langs root

ferrior30/gitbook,npracht/documentation,ZachLamb/gitbook,xcv58/gitbook,escopecz/documentation,Abhikos/gitbook,bjlxj2008/gitbook,mruse/gitbook,tzq668766/gitbook,gdbooks/gitbook,escopecz/documentation,qingying5810/gitbook,boyXiong/gitbook,palerdot/gitbook,ZachLamb/gitbook,Keystion/gitbook,megumiteam/documentation,jasonslyvia/gitbook,ryanswanson/gitbook,justinleoye/gitbook,a-moses/gitbook,jocr1627/gitbook,wewelove/gitbook,shibe97/gitbook,guiquanz/gitbook,wewelove/gitbook,switchspan/gitbook,gaearon/gitbook,tzq668766/gitbook,npracht/documentation,JohnTroony/gitbook,OriPekelman/gitbook,iflyup/gitbook,nycitt/gitbook,haamop/documentation,hujianfei1989/gitbook,tshoper/gitbook,JohnTroony/gitbook,ferrior30/gitbook,anrim/gitbook,xcv58/gitbook,rohan07/gitbook,hujianfei1989/gitbook,xiongjungit/gitbook,haamop/documentation,iamchenxin/gitbook,mautic/documentation,mautic/documentation,hongbinz/gitbook,iflyup/gitbook,grokcoder/gitbook,a-moses/gitbook,mruse/gitbook,CN-Sean/gitbook,lucciano/gitbook,sunlianghua/gitbook,thelastmile/gitbook,boyXiong/gitbook,justinleoye/gitbook,codepiano/gitbook,guiquanz/gitbook,snowsnail/gitbook,bradparks/gitbook,GitbookIO/gitbook,switchspan/gitbook,xxxhycl2010/gitbook,sudobashme/gitbook,OriPekelman/gitbook,shibe97/gitbook,megumiteam/documentation,sunlianghua/gitbook,2390183798/gitbook,iamchenxin/gitbook,webwlsong/gitbook,CN-Sean/gitbook,palerdot/gitbook,athiruban/gitbook,alex-dixon/gitbook,vehar/gitbook,bjlxj2008/gitbook,vehar/gitbook,qingying5810/gitbook,snowsnail/gitbook,gencer/gitbook,nycitt/gitbook,athiruban/gitbook,youprofit/gitbook,gaearon/gitbook,hongbinz/gitbook,codepiano/gitbook,strawluffy/gitbook,sudobashme/gitbook,FKV587/gitbook,youprofit/gitbook,FKV587/gitbook,jasonslyvia/gitbook,intfrr/gitbook,tshoper/gitbook,xiongjungit/gitbook,jocr1627/gitbook,gdbooks/gitbook,xxxhycl2010/gitbook,2390183798/gitbook,yaonphy/SwiftBlog,grokcoder/gitbook,minghe/gitbook,alex-dixon/gitbook,kamyu104/gitbook,rohan07/gitbook,kamyu104/gitbook,gencer/gitbook,JozoVilcek/gitbook,minghe/gitbook,thelastmile/gitbook,intfrr/gitbook,lucciano/gitbook,bradparks/gitbook,webwlsong/gitbook