polyhedron: use list when using index for Py 2.5
polyhedron: use list when using index for Py 2.5

shikil/sympy,Sumith1896/sympy,wyom/sympy,kumarkrishna/sympy,hargup/sympy,souravsingh/sympy,farhaanbukhsh/sympy,sunny94/temp,sahilshekhawat/sympy,emon10005/sympy,chaffra/sympy,chaffra/sympy,atsao72/sympy,ga7g08/sympy,VaibhavAgarwalVA/sympy,madan96/sympy,abhiii5459/sympy,Designist/sympy,wanglongqi/sympy,toolforger/sympy,kevalds51/sympy,wyom/sympy,skidzo/sympy,emon10005/sympy,kmacinnis/sympy,pandeyadarsh/sympy,sampadsaha5/sympy,lidavidm/sympy,cccfran/sympy,ChristinaZografou/sympy,maniteja123/sympy,souravsingh/sympy,moble/sympy,drufat/sympy,MechCoder/sympy,Titan-C/sympy,diofant/diofant,shipci/sympy,Vishluck/sympy,MechCoder/sympy,garvitr/sympy,dqnykamp/sympy,Mitchkoens/sympy,drufat/sympy,Curious72/sympy,kaushik94/sympy,jerli/sympy,jamesblunt/sympy,maniteja123/sympy,kmacinnis/sympy,sahilshekhawat/sympy,bukzor/sympy,hrashk/sympy,atreyv/sympy,meghana1995/sympy,yashsharan/sympy,AunShiLord/sympy,lidavidm/sympy,vipulroxx/sympy,sunny94/temp,grevutiu-gabriel/sympy,abloomston/sympy,Sumith1896/sympy,kmacinnis/sympy,abloomston/sympy,maniteja123/sympy,shipci/sympy,kaichogami/sympy,cccfran/sympy,amitjamadagni/sympy,aktech/sympy,Curious72/sympy,abloomston/sympy,postvakje/sympy,moble/sympy,sahilshekhawat/sympy,kevalds51/sympy,mafiya69/sympy,Curious72/sympy,yashsharan/sympy,mcdaniel67/sympy,liangjiaxing/sympy,MridulS/sympy,hrashk/sympy,sampadsaha5/sympy,bukzor/sympy,lindsayad/sympy,pbrady/sympy,liangjiaxing/sympy,wanglongqi/sympy,iamutkarshtiwari/sympy,kevalds51/sympy,Davidjohnwilson/sympy,postvakje/sympy,iamutkarshtiwari/sympy,MechCoder/sympy,oliverlee/sympy,yukoba/sympy,shipci/sympy,yukoba/sympy,atreyv/sympy,beni55/sympy,garvitr/sympy,Mitchkoens/sympy,cswiercz/sympy,asm666/sympy,mafiya69/sympy,rahuldan/sympy,drufat/sympy,jbbskinny/sympy,Sumith1896/sympy,souravsingh/sympy,mcdaniel67/sympy,toolforger/sympy,sunny94/temp,skidzo/sympy,hargup/sympy,kaushik94/sympy,Davidjohnwilson/sympy,lidavidm/sympy,skirpichev/omg,AkademieOlympia/sympy,kumarkrishna/sympy,VaibhavAgarwalVA/sympy,AkademieOlympia/sympy,pandeyadarsh/sympy,liangjiaxing/sympy,ga7g08/sympy,dqnykamp/sympy,shikil/sympy,lindsayad/sympy,cswiercz/sympy,ga7g08/sympy,atreyv/sympy,debugger22/sympy,Arafatk/sympy,farhaanbukhsh/sympy,ahhda/sympy,jerli/sympy,Davidjohnwilson/sympy,saurabhjn76/sympy,garvitr/sympy,saurabhjn76/sympy,dqnykamp/sympy,Arafatk/sympy,Vishluck/sympy,wyom/sympy,beni55/sympy,Shaswat27/sympy,grevutiu-gabriel/sympy,pandeyadarsh/sympy,jbbskinny/sympy,beni55/sympy,MridulS/sympy,meghana1995/sympy,meghana1995/sympy,Titan-C/sympy,hrashk/sympy,jaimahajan1997/sympy,Arafatk/sympy,grevutiu-gabriel/sympy,farhaanbukhsh/sympy,asm666/sympy,kaichogami/sympy,shikil/sympy,rahuldan/sympy,madan96/sympy,pbrady/sympy,sampadsaha5/sympy,asm666/sympy,AunShiLord/sympy,chaffra/sympy,iamutkarshtiwari/sympy,Mitchkoens/sympy,aktech/sympy,AkademieOlympia/sympy,VaibhavAgarwalVA/sympy,mcdaniel67/sympy,debugger22/sympy,Gadal/sympy,kumarkrishna/sympy,ahhda/sympy,oliverlee/sympy,atsao72/sympy,kaichogami/sympy,aktech/sympy,ChristinaZografou/sympy,atsao72/sympy,emon10005/sympy,mafiya69/sympy,cccfran/sympy,toolforger/sympy,madan96/sympy,Titan-C/sympy,hargup/sympy,sahmed95/sympy,Designist/sympy,ChristinaZografou/sympy,abhiii5459/sympy,amitjamadagni/sympy,Designist/sympy,jamesblunt/sympy,postvakje/sympy,jamesblunt/sympy,moble/sympy,cswiercz/sympy,jerli/sympy,kaushik94/sympy,Shaswat27/sympy,wanglongqi/sympy,jaimahajan1997/sympy,debugger22/sympy,jbbskinny/sympy,Gadal/sympy,AunShiLord/sympy,sahmed95/sympy,abhiii5459/sympy,rahuldan/sympy,vipulroxx/sympy,Gadal/sympy,sahmed95/sympy,MridulS/sympy,yukoba/sympy,yashsharan/sympy,skidzo/sympy,saurabhjn76/sympy,ahhda/sympy,Shaswat27/sympy,oliverlee/sympy,pbrady/sympy,vipulroxx/sympy,jaimahajan1997/sympy,bukzor/sympy,Vishluck/sympy,lindsayad/sympy