Skip block reduce/replicate tests if skimage is not available
Skip block reduce/replicate tests if skimage is not available

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