This avoids creating a second derivation to copy things from the
original. The new themes are now fixed output.

game.json now contains a dictionary of old game hashes. I have added
them for the last 3 releases.

- add script to generate hashes

  Makes it much easier to update game.json file.

- add updateScript meta

  This adds some info on the ./update.sh updateScript now available.

- cleanup updateScript

  - Add some more systems
  - Correctly detect source extensions (.zip or .tar.bz2)
  - Proper bash quoting

- fix update.sh

  - correctly detect latest df version
  - append to game.json instead of overwriting it

- update hashes for 44.12

This will make it easier for people to access old versions.

You can now access attributes like:

- dwarf-fortress_0_44_11
- dwarf-fortress_0_43_05
- etc.

Now the output of “nix-env” should be:

$ nix-env -qa -f . -A dwarf-fortress-packages
afro-graphics-44.10
autoreiv-44.03
cla-44.xx-v25
dwarf-fortress-0.43.05
dwarf-fortress-0.44.05
dwarf-fortress-0.44.09
dwarf-fortress-0.44.10
dwarf-fortress-0.44.11
dwarf-fortress-0.44.12
dwarf-therapist-40.1.0
gemset-44.10a
ironhand-44.10
jolly-bastion-44.10
legends-browser-1.17.1
mayday-44.10
obsidian-44.10
phoebus-44.10
rally-ho-44.10
soundsense-2016-1_196
spacefox-44.10a
taffer-44.10a
tergel-44.03
wanderlust-44.10

Dwarf Fortress refactors