TST: ubuntu 16.x no longer supported
TST: ubuntu 16.x no longer supported

lpsinger/astropy,saimn/astropy,larrybradley/astropy,astropy/astropy,larrybradley/astropy,pllim/astropy,astropy/astropy,lpsinger/astropy,pllim/astropy,larrybradley/astropy,astropy/astropy,saimn/astropy,saimn/astropy,pllim/astropy,larrybradley/astropy,saimn/astropy,StuartLittlefair/astropy,pllim/astropy,mhvk/astropy,astropy/astropy,mhvk/astropy,astropy/astropy,lpsinger/astropy,larrybradley/astropy,StuartLittlefair/astropy,mhvk/astropy,lpsinger/astropy,StuartLittlefair/astropy,pllim/astropy,lpsinger/astropy,StuartLittlefair/astropy,mhvk/astropy,StuartLittlefair/astropy,mhvk/astropy,saimn/astropy