Fix address in GPL header

Box/Main.cpp

COPYING

Common/ColorTable.cpp

Common/ColorTable.h

Common/Colors.h

Common/Context.cpp

Common/Context.h

Common/DefaultOptions.h

Common/GetOptions.cpp

Common/GetOptions.h

Common/Gmsh.h

Common/GmshUI.h

Common/Message.h

Common/Options.cpp

Common/Options.h

Common/Timer.cpp

Common/Timer.h

Common/Views.cpp

Common/Views.h

DataStr/List.cpp