Change the default formatter in `quantity_support` and allow to modify it.
Change the default formatter in `quantity_support` and allow to modify it.

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