Add handle_first option to risch_integrate() and fix a bug
Add handle_first option to risch_integrate() and fix a bug

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