update to use os.path.join instead of adding path elements
update to use os.path.join instead of adding path elements

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