Add test to check behavior of adding scalar column to empty table.
Add test to check behavior of adding scalar column to empty table.

dhomeier/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,aleksandr-bakanov/astropy,mhvk/astropy,larrybradley/astropy,mhvk/astropy,lpsinger/astropy,larrybradley/astropy,lpsinger/astropy,saimn/astropy,mhvk/astropy,astropy/astropy,astropy/astropy,astropy/astropy,pllim/astropy,dhomeier/astropy,astropy/astropy,StuartLittlefair/astropy,mhvk/astropy,dhomeier/astropy,lpsinger/astropy,lpsinger/astropy,pllim/astropy,pllim/astropy,StuartLittlefair/astropy,pllim/astropy,lpsinger/astropy,saimn/astropy,astropy/astropy,larrybradley/astropy,saimn/astropy,StuartLittlefair/astropy,saimn/astropy,StuartLittlefair/astropy,mhvk/astropy,aleksandr-bakanov/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,saimn/astropy,StuartLittlefair/astropy,larrybradley/astropy,pllim/astropy,dhomeier/astropy