New GoG installer for icewind-dale-2

[Edward Allcutt]

Current (testing) gdp does not recognise setup_icewind_dale2_2.1.0.13.exe 
which is the current downloadable artifact from GoG. When given it it 
prints:

Please report this unknown archive to game-data-packager at packages.debian.org

   1370678024 9a68fdabdaff58bebc67092d47d4174e setup_icewind_dale2_2.1.0.13.exe
   990721995c7b9640efc4bc97bff30fba17fc3b5c  setup_icewind_dale2_2.1.0.13.exe

I've extracted/edited/replaced the icewind-dale-2.* files in vfs.zip by 
hand and subsequently gdp accepts the new archive and recognizes all the 
contents. Just adding the above to the existing metadata seems to be good 
enough.

-- 
Edward Allcutt