Added getitem for coordinates to allow indexing
Added getitem for coordinates to allow indexing

closes #1508

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