added bit to docs Makefile to build _static directory that git doesn't create
added bit to docs Makefile to build _static directory that git doesn't create

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