It's necessary to do this in order to fix ckb's compilation, now that
fixupPhase rejects derivation results containing references to the temporary
build directory. It seems like good practice so I've added it to the
other packages that I maintain.
Previously, the entire installation was copied to $out/opt/unigine/valley.
Using $out/lib instead of $out/opt would be more consistent with other Nix packages.
The upstream version is "1.0", so that's what the version of the Nix package should be too.
When I packaged this I wasn't aware that a Nix package could update without its version number
increasing, so I added an extra "release version" (like Arch Linux packages). Of course, this
isn't necessary.
