BUG: Make all filter design functions return empty arrays for N=0
BUG: Make all filter design functions return empty arrays for N=0

Dapid/scipy,njwilson23/scipy,bkendzior/scipy,bkendzior/scipy,argriffing/scipy,jsilter/scipy,arokem/scipy,newemailjdm/scipy,befelix/scipy,surhudm/scipy,WillieMaddox/scipy,zaxliu/scipy,endolith/scipy,rgommers/scipy,ndchorley/scipy,piyush0609/scipy,newemailjdm/scipy,maciejkula/scipy,matthewalbani/scipy,jamestwebber/scipy,ilayn/scipy,mortada/scipy,hainm/scipy,kleskjr/scipy,ales-erjavec/scipy,witcxc/scipy,pizzathief/scipy,kalvdans/scipy,Dapid/scipy,Stefan-Endres/scipy,witcxc/scipy,jamestwebber/scipy,andyfaff/scipy,ChanderG/scipy,vhaasteren/scipy,newemailjdm/scipy,lukauskas/scipy,gertingold/scipy,zxsted/scipy,maniteja123/scipy,jamestwebber/scipy,matthewalbani/scipy,jjhelmus/scipy,pbrod/scipy,vberaudi/scipy,mdhaber/scipy,pnedunuri/scipy,pnedunuri/scipy,ortylp/scipy,Dapid/scipy,vberaudi/scipy,ilayn/scipy,minhlongdo/scipy,zaxliu/scipy,jsilter/scipy,gdooper/scipy,giorgiop/scipy,bkendzior/scipy,Dapid/scipy,jjhelmus/scipy,giorgiop/scipy,haudren/scipy,pbrod/scipy,rgommers/scipy,mtrbean/scipy,jamestwebber/scipy,grlee77/scipy,raoulbq/scipy,Newman101/scipy,jakevdp/scipy,e-q/scipy,pizzathief/scipy,e-q/scipy,zxsted/scipy,matthewalbani/scipy,anntzer/scipy,ChanderG/scipy,mhogg/scipy,Kamp9/scipy,gfyoung/scipy,kalvdans/scipy,cpaulik/scipy,WarrenWeckesser/scipy,dch312/scipy,haudren/scipy,larsmans/scipy,jsilter/scipy,Kamp9/scipy,tylerjereddy/scipy,vhaasteren/scipy,gef756/scipy,ChanderG/scipy,Gillu13/scipy,FRidh/scipy,ales-erjavec/scipy,anntzer/scipy,Kamp9/scipy,richardotis/scipy,FRidh/scipy,mhogg/scipy,richardotis/scipy,pyramania/scipy,pbrod/scipy,Gillu13/scipy,sonnyhu/scipy,Newman101/scipy,vhaasteren/scipy,rmcgibbo/scipy,nonhermitian/scipy,vigna/scipy,gef756/scipy,Stefan-Endres/scipy,zerothi/scipy,perimosocordiae/scipy,efiring/scipy,dominicelse/scipy,zerothi/scipy,woodscn/scipy,richardotis/scipy,kleskjr/scipy,Eric89GXL/scipy,nvoron23/scipy,chatcannon/scipy,sonnyhu/scipy,vhaasteren/scipy,Eric89GXL/scipy,jonycgn/scipy,mikebenfield/scipy,mgaitan/scipy,futurulus/scipy,WarrenWeckesser/scipy,aeklant/scipy,minhlongdo/scipy,perimosocordiae/scipy,zxsted/scipy,ogrisel/scipy,andyfaff/scipy,surhudm/scipy,mortonjt/scipy,Gillu13/scipy,mtrbean/scipy,andyfaff/scipy,josephcslater/scipy,mdhaber/scipy,perimosocordiae/scipy,Stefan-Endres/scipy,aarchiba/scipy,gfyoung/scipy,befelix/scipy,fredrikw/scipy,pnedunuri/scipy,e-q/scipy,mgaitan/scipy,Gillu13/scipy,felipebetancur/scipy,vigna/scipy,behzadnouri/scipy,sonnyhu/scipy,fredrikw/scipy,argriffing/scipy,niknow/scipy,jakevdp/scipy,zxsted/scipy,lhilt/scipy,ilayn/scipy,andim/scipy,jonycgn/scipy,befelix/scipy,anielsen001/scipy,vanpact/scipy,nvoron23/scipy,jseabold/scipy,rmcgibbo/scipy,WillieMaddox/scipy,scipy/scipy,e-q/scipy,dch312/scipy,fernand/scipy,aeklant/scipy,WillieMaddox/scipy,ortylp/scipy,scipy/scipy,aman-iitj/scipy,nonhermitian/scipy,mingwpy/scipy,niknow/scipy,jjhelmus/scipy,futurulus/scipy,ogrisel/scipy,mingwpy/scipy,piyush0609/scipy,vanpact/scipy,Newman101/scipy,newemailjdm/scipy,aman-iitj/scipy,giorgiop/scipy,behzadnouri/scipy,mortada/scipy,behzadnouri/scipy,FRidh/scipy,maniteja123/scipy,anielsen001/scipy,person142/scipy,jor-/scipy,futurulus/scipy,Shaswat27/scipy,vigna/scipy,mdhaber/scipy,mtrbean/scipy,maciejkula/scipy,aman-iitj/scipy,Stefan-Endres/scipy,mgaitan/scipy,ortylp/scipy,petebachant/scipy,petebachant/scipy,andim/scipy,hainm/scipy,kalvdans/scipy,gertingold/scipy,jor-/scipy,efiring/scipy,ilayn/scipy,gef756/scipy,Newman101/scipy,zaxliu/scipy,zaxliu/scipy,josephcslater/scipy,mgaitan/scipy,pbrod/scipy,mortonjt/scipy,fernand/scipy,piyush0609/scipy,befelix/scipy,ilayn/scipy,vhaasteren/scipy,mortada/scipy,ndchorley/scipy,woodscn/scipy,perimosocordiae/scipy,vberaudi/scipy,jsilter/scipy,anielsen001/scipy,Eric89GXL/scipy,jjhelmus/scipy,scipy/scipy,ortylp/scipy,endolith/scipy,andyfaff/scipy,Shaswat27/scipy,zaxliu/scipy,ogrisel/scipy,cpaulik/scipy,Srisai85/scipy,sauliusl/scipy,nvoron23/scipy,zerothi/scipy,felipebetancur/scipy,mortonjt/scipy,grlee77/scipy,pyramania/scipy,lukauskas/scipy,minhlongdo/scipy,larsmans/scipy,mhogg/scipy,Stefan-Endres/scipy,apbard/scipy,FRidh/scipy,person142/scipy,felipebetancur/scipy,fredrikw/scipy,Srisai85/scipy,WarrenWeckesser/scipy,aarchiba/scipy,jonycgn/scipy,pschella/scipy,sriki18/scipy,hainm/scipy,behzadnouri/scipy,ChanderG/scipy,apbard/scipy,jor-/scipy,mhogg/scipy,andim/scipy,vigna/scipy,piyush0609/scipy,pyramania/scipy,kleskjr/scipy,maniteja123/scipy,kalvdans/scipy,niknow/scipy,endolith/scipy,tylerjereddy/scipy,larsmans/scipy,gertingold/scipy,endolith/scipy,lhilt/scipy,Shaswat27/scipy,njwilson23/scipy,arokem/scipy,aarchiba/scipy,arokem/scipy,fernand/scipy,nvoron23/scipy,fredrikw/scipy,matthew-brett/scipy,vhaasteren/scipy,Kamp9/scipy,kleskjr/scipy,woodscn/scipy,ogrisel/scipy,nonhermitian/scipy,maniteja123/scipy,niknow/scipy,sriki18/scipy,mingwpy/scipy,chatcannon/scipy,vanpact/scipy,gef756/scipy,pizzathief/scipy,efiring/scipy,perimosocordiae/scipy,efiring/scipy,chatcannon/scipy,Srisai85/scipy,mikebenfield/scipy,scipy/scipy,cpaulik/scipy,person142/scipy,aarchiba/scipy,jonycgn/scipy,behzadnouri/scipy,gef756/scipy,pizzathief/scipy,mikebenfield/scipy,endolith/scipy,jor-/scipy,lhilt/scipy,aeklant/scipy,ales-erjavec/scipy,pbrod/scipy,haudren/scipy,matthew-brett/scipy,niknow/scipy,Newman101/scipy,raoulbq/scipy,Gillu13/scipy,josephcslater/scipy,matthewalbani/scipy,dominicelse/scipy,andyfaff/scipy,scipy/scipy,Newman101/scipy,pyramania/scipy,lukauskas/scipy,perimosocordiae/scipy,haudren/scipy,gdooper/scipy,WillieMaddox/scipy,richardotis/scipy,piyush0609/scipy,person142/scipy,zerothi/scipy,niknow/scipy,njwilson23/scipy,larsmans/scipy,raoulbq/scipy,vigna/scipy,pschella/scipy,nmayorov/scipy,sauliusl/scipy,njwilson23/scipy,bkendzior/scipy,aarchiba/scipy,surhudm/scipy,aeklant/scipy,anntzer/scipy,ales-erjavec/scipy,felipebetancur/scipy,cpaulik/scipy,rmcgibbo/scipy,hainm/scipy,pnedunuri/scipy,bkendzior/scipy,anntzer/scipy,pschella/scipy,endolith/scipy,arokem/scipy,dch312/scipy,maniteja123/scipy,ndchorley/scipy,futurulus/scipy,Eric89GXL/scipy,Srisai85/scipy,Shaswat27/scipy,grlee77/scipy,lukauskas/scipy,matthewalbani/scipy,vanpact/scipy,mikebenfield/scipy,kleskjr/scipy,matthew-brett/scipy,sauliusl/scipy,dch312/scipy,mikebenfield/scipy,minhlongdo/scipy,argriffing/scipy,gertingold/scipy,jsilter/scipy,pbrod/scipy,gdooper/scipy,anntzer/scipy,sauliusl/scipy,trankmichael/scipy,tylerjereddy/scipy,pizzathief/scipy,nvoron23/scipy,tylerjereddy/scipy,petebachant/scipy,jakevdp/scipy,jamestwebber/scipy,WarrenWeckesser/scipy,raoulbq/scipy,ales-erjavec/scipy,minhlongdo/scipy,matthew-brett/scipy,futurulus/scipy,jor-/scipy,Shaswat27/scipy,mgaitan/scipy,newemailjdm/scipy,nonhermitian/scipy,andim/scipy,anielsen001/scipy,zaxliu/scipy,richardotis/scipy,grlee77/scipy,gdooper/scipy,jseabold/scipy,pyramania/scipy,mtrbean/scipy,minhlongdo/scipy,argriffing/scipy,fernand/scipy,mdhaber/scipy,surhudm/scipy,maciejkula/scipy,mortonjt/scipy,gfyoung/scipy,larsmans/scipy,andyfaff/scipy,zerothi/scipy,maciejkula/scipy,zerothi/scipy,andim/scipy,Eric89GXL/scipy,fredrikw/scipy,surhudm/scipy,jakevdp/scipy,ilayn/scipy,njwilson23/scipy,rgommers/scipy,kleskjr/scipy,jjhelmus/scipy,mortonjt/scipy,rmcgibbo/scipy,piyush0609/scipy,jseabold/scipy,chatcannon/scipy,hainm/scipy,pschella/scipy,chatcannon/scipy,ogrisel/scipy,matthew-brett/scipy,haudren/scipy,trankmichael/scipy,Eric89GXL/scipy,mortonjt/scipy,gertingold/scipy,mdhaber/scipy,fernand/scipy,WillieMaddox/scipy,petebachant/scipy,jseabold/scipy,petebachant/scipy,petebachant/scipy,rgommers/scipy,WillieMaddox/scipy,nmayorov/scipy,jakevdp/scipy,apbard/scipy,giorgiop/scipy,Dapid/scipy,sauliusl/scipy,woodscn/scipy,ndchorley/scipy,aman-iitj/scipy,lhilt/scipy,scipy/scipy,aeklant/scipy,dominicelse/scipy,vanpact/scipy,lukauskas/scipy,apbard/scipy,e-q/scipy,dominicelse/scipy,ortylp/scipy,befelix/scipy,gdooper/scipy,sonnyhu/scipy,Stefan-Endres/scipy,jonycgn/scipy,fernand/scipy,josephcslater/scipy,cpaulik/scipy,Kamp9/scipy,maniteja123/scipy,witcxc/scipy,witcxc/scipy,newemailjdm/scipy,Shaswat27/scipy,surhudm/scipy,sonnyhu/scipy,giorgiop/scipy,futurulus/scipy,nvoron23/scipy,gfyoung/scipy,cpaulik/scipy,njwilson23/scipy,sriki18/scipy,vanpact/scipy,giorgiop/scipy,nonhermitian/scipy,nmayorov/scipy,person142/scipy,woodscn/scipy,woodscn/scipy,sonnyhu/scipy,trankmichael/scipy,rgommers/scipy,mortada/scipy,apbard/scipy,Dapid/scipy,ChanderG/scipy,tylerjereddy/scipy,mortada/scipy,mdhaber/scipy,arokem/scipy,behzadnouri/scipy,anntzer/scipy,sriki18/scipy,argriffing/scipy,mtrbean/scipy,efiring/scipy,nmayorov/scipy,WarrenWeckesser/scipy,fredrikw/scipy,felipebetancur/scipy,josephcslater/scipy,lhilt/scipy,trankmichael/scipy,vberaudi/scipy,dch312/scipy,WarrenWeckesser/scipy,argriffing/scipy,kalvdans/scipy,gfyoung/scipy,vberaudi/scipy,efiring/scipy,witcxc/scipy,larsmans/scipy,mhogg/scipy,sriki18/scipy,sauliusl/scipy,mhogg/scipy,chatcannon/scipy,jseabold/scipy,mtrbean/scipy,raoulbq/scipy,trankmichael/scipy,mingwpy/scipy,mortada/scipy,andim/scipy,pnedunuri/scipy,pnedunuri/scipy,rmcgibbo/scipy,hainm/scipy,Kamp9/scipy,felipebetancur/scipy,vberaudi/scipy,jseabold/scipy,FRidh/scipy,mingwpy/scipy,zxsted/scipy,maciejkula/scipy,dominicelse/scipy,gef756/scipy,raoulbq/scipy,pschella/scipy,ChanderG/scipy,ndchorley/scipy,mgaitan/scipy,aman-iitj/scipy,rmcgibbo/scipy,trankmichael/scipy,richardotis/scipy,mingwpy/scipy,Srisai85/scipy,ortylp/scipy,Srisai85/scipy,nmayorov/scipy,ales-erjavec/scipy,jonycgn/scipy,ndchorley/scipy,FRidh/scipy,sriki18/scipy,zxsted/scipy,grlee77/scipy,aman-iitj/scipy,anielsen001/scipy,haudren/scipy,lukauskas/scipy,Gillu13/scipy,anielsen001/scipy