Add neutrino mass information to __repr__ for cosmology objects.
Add neutrino mass information to __repr__ for cosmology objects.

* Adjust __repr__ for FLRW and all subclasses to output neutrino information.
  For consistency, since %r is used for m_nu (a quantity), also use %r
  for Tcmb0 and H0.
* closes #1302

pllim/astropy,StuartLittlefair/astropy,kelle/astropy,dhomeier/astropy,larrybradley/astropy,MSeifert04/astropy,saimn/astropy,joergdietrich/astropy,bsipocz/astropy,saimn/astropy,larrybradley/astropy,DougBurke/astropy,astropy/astropy,joergdietrich/astropy,pllim/astropy,funbaker/astropy,DougBurke/astropy,MSeifert04/astropy,pllim/astropy,astropy/astropy,pllim/astropy,AustereCuriosity/astropy,lpsinger/astropy,funbaker/astropy,lpsinger/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,kelle/astropy,stargaser/astropy,bsipocz/astropy,tbabej/astropy,mhvk/astropy,DougBurke/astropy,StuartLittlefair/astropy,astropy/astropy,stargaser/astropy,tbabej/astropy,joergdietrich/astropy,saimn/astropy,kelle/astropy,pllim/astropy,funbaker/astropy,dhomeier/astropy,funbaker/astropy,kelle/astropy,bsipocz/astropy,AustereCuriosity/astropy,joergdietrich/astropy,AustereCuriosity/astropy,dhomeier/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,mhvk/astropy,dhomeier/astropy,saimn/astropy,mhvk/astropy,tbabej/astropy,joergdietrich/astropy,tbabej/astropy,AustereCuriosity/astropy,astropy/astropy,AustereCuriosity/astropy,larrybradley/astropy,larrybradley/astropy,bsipocz/astropy,stargaser/astropy,aleksandr-bakanov/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,tbabej/astropy,astropy/astropy,lpsinger/astropy,MSeifert04/astropy,mhvk/astropy,StuartLittlefair/astropy,DougBurke/astropy,saimn/astropy,stargaser/astropy,lpsinger/astropy,aleksandr-bakanov/astropy,kelle/astropy,mhvk/astropy,dhomeier/astropy,lpsinger/astropy