Changed MatExpr symbol printing
Changed MatExpr symbol printing

It now looks better in the common case (i.e. a[2,3] -> a_23)
But reverts to ugly system when MatMul needs the function objects for
(A*B)[2,3] = Summation ...

This split is somewhat problematic but I think the aesthetics are worth the
rare confusion when someone actually needs to sum object

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