implemented initializer with an nddata object. Next step is doing the same for nderror
implemented initializer with an nddata object. Next step is doing the same for nderror

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