Updated Travis YML dependency versions. Exclusively use Astropy dev until astropy/astropy#4748 is in the stable version (v1.2)
Updated Travis YML dependency versions. Exclusively use Astropy dev until astropy/astropy#4748 is in the stable version (v1.2)

stscieisenhamer/ginga,rupak0577/ginga,ejeschke/ginga,pllim/ginga,pllim/ginga,rupak0577/ginga,naojsoft/ginga,naojsoft/ginga,naojsoft/ginga,rupak0577/ginga,ejeschke/ginga,pllim/ginga,stscieisenhamer/ginga,stscieisenhamer/ginga,ejeschke/ginga