update Float._new since Float(Integer) returns Float
update Float._new since Float(Integer) returns Float

Also, add more to the docstring of mpf_norm regarding what
it does and doesn't do.  Here is an example of ill-formed
mpf's giving bad results:

>>> mpf_norm((3,123455,0,4), 3)
(1, 1929L, 6, -2)  <======= negative bitcount
>>> mpf_norm((3,123455,0,22), 1) <====== hangs

Both of these problems would not occur if the proper bitcount
of 17 were used instead of 4 or 22

>>> mpf_norm((3,123455,0,17),3)
(3, 1, 17, 1)
>>> mpf_norm((3,123455,0,17),1)
(3, 1, 17, 1)

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