travis: install imagemagick & librsvg2-bin for sphinx
travis: install imagemagick & librsvg2-bin for sphinx

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