add tests for array separations
add tests for array separations

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