Considering Blender's license, I don't think he meant that you are obligated to change the license. I think he was making the suggestion. However, there always exists the possibility that I am misremembering the Blender license (though I doubt it in this case). Regardless, GPL licenses should help the code get adopted into projects like Armory. Without that license or a VERY similar one, I don't think Armory will be integrated with it. Again though, it's up to the individual people who add code to the main build and the forks of those builds and at this point it's just @lubos on that one.