Added 'rewrite_intractable' and several typo fixes.
Added 'rewrite_intractable' and several typo fixes.

VaibhavAgarwalVA/sympy,souravsingh/sympy,sampadsaha5/sympy,emon10005/sympy,aktech/sympy,oliverlee/sympy,sahilshekhawat/sympy,hrashk/sympy,debugger22/sympy,jamesblunt/sympy,pandeyadarsh/sympy,abloomston/sympy,MridulS/sympy,Sumith1896/sympy,jaimahajan1997/sympy,Curious72/sympy,ChristinaZografou/sympy,shipci/sympy,jbbskinny/sympy,sunny94/temp,jerli/sympy,saurabhjn76/sympy,Designist/sympy,cccfran/sympy,sahmed95/sympy,mcdaniel67/sympy,jerli/sympy,jamesblunt/sympy,hargup/sympy,liangjiaxing/sympy,Titan-C/sympy,flacjacket/sympy,liangjiaxing/sympy,drufat/sympy,pbrady/sympy,atsao72/sympy,ahhda/sympy,maniteja123/sympy,farhaanbukhsh/sympy,farhaanbukhsh/sympy,wanglongqi/sympy,AkademieOlympia/sympy,asm666/sympy,bukzor/sympy,Titan-C/sympy,shikil/sympy,jaimahajan1997/sympy,sahmed95/sympy,MridulS/sympy,meghana1995/sympy,diofant/diofant,pbrady/sympy,iamutkarshtiwari/sympy,meghana1995/sympy,Mitchkoens/sympy,beni55/sympy,MechCoder/sympy,meghana1995/sympy,madan96/sympy,atreyv/sympy,asm666/sympy,cccfran/sympy,AunShiLord/sympy,pbrady/sympy,shipci/sympy,toolforger/sympy,oliverlee/sympy,moble/sympy,emon10005/sympy,ChristinaZografou/sympy,sunny94/temp,Vishluck/sympy,wyom/sympy,kaichogami/sympy,lindsayad/sympy,skidzo/sympy,bukzor/sympy,oliverlee/sympy,skirpichev/omg,VaibhavAgarwalVA/sympy,wyom/sympy,saurabhjn76/sympy,ahhda/sympy,Arafatk/sympy,dqnykamp/sympy,shikil/sympy,beni55/sympy,AunShiLord/sympy,maniteja123/sympy,chaffra/sympy,atsao72/sympy,cswiercz/sympy,Sumith1896/sympy,mafiya69/sympy,kaichogami/sympy,skidzo/sympy,ga7g08/sympy,shikil/sympy,sampadsaha5/sympy,ChristinaZografou/sympy,toolforger/sympy,kumarkrishna/sympy,shipci/sympy,rahuldan/sympy,mcdaniel67/sympy,aktech/sympy,abhiii5459/sympy,Gadal/sympy,kevalds51/sympy,hrashk/sympy,garvitr/sympy,Arafatk/sympy,lidavidm/sympy,abloomston/sympy,lidavidm/sympy,moble/sympy,Mitchkoens/sympy,MridulS/sympy,maniteja123/sympy,Vishluck/sympy,Shaswat27/sympy,souravsingh/sympy,amitjamadagni/sympy,yukoba/sympy,kmacinnis/sympy,grevutiu-gabriel/sympy,Titan-C/sympy,lidavidm/sympy,grevutiu-gabriel/sympy,saurabhjn76/sympy,lindsayad/sympy,rahuldan/sympy,atreyv/sympy,cccfran/sympy,vipulroxx/sympy,Designist/sympy,abloomston/sympy,kmacinnis/sympy,farhaanbukhsh/sympy,postvakje/sympy,yukoba/sympy,ga7g08/sympy,Gadal/sympy,srjoglekar246/sympy,chaffra/sympy,kaushik94/sympy,pandeyadarsh/sympy,debugger22/sympy,beni55/sympy,rahuldan/sympy,jbbskinny/sympy,iamutkarshtiwari/sympy,Davidjohnwilson/sympy,emon10005/sympy,hargup/sympy,madan96/sympy,kmacinnis/sympy,vipulroxx/sympy,garvitr/sympy,Gadal/sympy,AunShiLord/sympy,iamutkarshtiwari/sympy,kevalds51/sympy,Designist/sympy,Sumith1896/sympy,AkademieOlympia/sympy,ahhda/sympy,atreyv/sympy,Arafatk/sympy,jamesblunt/sympy,Curious72/sympy,yashsharan/sympy,amitjamadagni/sympy,drufat/sympy,postvakje/sympy,mcdaniel67/sympy,dqnykamp/sympy,grevutiu-gabriel/sympy,sunny94/temp,chaffra/sympy,postvakje/sympy,garvitr/sympy,jerli/sympy,kevalds51/sympy,toolforger/sympy,liangjiaxing/sympy,cswiercz/sympy,hrashk/sympy,Curious72/sympy,drufat/sympy,sampadsaha5/sympy,jbbskinny/sympy,pandeyadarsh/sympy,MechCoder/sympy,Shaswat27/sympy,mafiya69/sympy,kaushik94/sympy,Vishluck/sympy,skidzo/sympy,kaushik94/sympy,moble/sympy,Davidjohnwilson/sympy,mafiya69/sympy,souravsingh/sympy,AkademieOlympia/sympy,Mitchkoens/sympy,jaimahajan1997/sympy,sahilshekhawat/sympy,kaichogami/sympy,sahilshekhawat/sympy,ga7g08/sympy,kumarkrishna/sympy,yukoba/sympy,hargup/sympy,asm666/sympy,madan96/sympy,abhiii5459/sympy,bukzor/sympy,wanglongqi/sympy,aktech/sympy,cswiercz/sympy,sahmed95/sympy,Shaswat27/sympy,kumarkrishna/sympy,MechCoder/sympy,yashsharan/sympy,wanglongqi/sympy,lindsayad/sympy,vipulroxx/sympy,yashsharan/sympy,abhiii5459/sympy,Davidjohnwilson/sympy,dqnykamp/sympy,VaibhavAgarwalVA/sympy,atsao72/sympy,debugger22/sympy,wyom/sympy