Fix SymPy to import in Jython
Fix SymPy to import in Jython

The definition of __slots__ in AssumeMixin was causing some problems in
Jython, so we don't define it if we are in Jython ("import java" works).
 See issue 1233 and Jython issue 1777
(http://bugs.jython.org/issue1777).  Thanks to Alan Kennedy for
suggesting this fix.

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