Apply seeds per save instead of globally.

[tinyhoot]

Randomising, restarting the application, starting a new game, then realising the seed was tosh is an annoying process. It also prevents playing more than one seed at once. An improved save/load system must:

• Apply changes on save load rather than application start; remove need for reloading the game completely.
• Provide a way to reset all changes, including anything registered with Nautilus.
  • In particular, make this accessible and/or mandatory for all logic modules.
• Move the global mod savefile to a game save specific file instead.