License upgrade from by-sa 3.0 to 4.0
Switch from Creative Commons license "Attribution-ShareAlike 4.0" (by-sa) from version 3.0 to 4.0.
This software is always meant to be compatible to GPL.
Switch from Creative Commons license "Attribution-ShareAlike 4.0" (by-sa) from version 3.0 to 4.0.
This software is always meant to be compatible to GPL.