tuxpaint: 0.9.24 -> 0.9.27; clarify license
tuxpaint: 0.9.24 -> 0.9.27; clarify license

It's not right for everything to be in nativeBuildInputs, but most of
the dependencies will never cross-compile anyway, so I'm just going to
leave it alone.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs