Fixed the "Imminent Nova" event firing a dozen times per empire (for real this time).

Ringworld sections are no longer vaporized, merely rendered uninhabitable and irreparable.

- Bugfix: The "Imminent Nova" event will no longer fire a dozen times per empire. This bug might happen one more time in existing saves if it's already been triggered, but after that it should be fixed for good.
- Stars will now visibly suffer a core collapse and shrink before going supernova.

I forget, lol.

- Updated to 3.1.
- Major rebuild to improve optimization and playability.
- Lots and lots of bugfixing.
- You can now see the date of the imminent supernova, rather than being limited to a day-by-day countdown.
- The two naturally-occurring Type II supernovas no longer use prescripted systems; they instead choose existing ones within certain criteria.
- Fixed the gamma-ray burst event chain not occurring.
- Improved and expanded the primitive ark event chain.

Supernovae will now wipe out any Terraforming Candidates in the system (not that you could do anything with them anyway).

The recurring nova system will no longer go nova if it's been destroyed by a Star Eater.

Improved the mechanic by which players discover an imminent supernova (for real this time).

- Updated to 3.0.
- Improved the mechanic by which players discover an imminent supernova.
- Added some new effects from Nemesis.
- Temporarily removed the Gaia World Hive Mind empire.
- The Ruined Dyson Sphere supernova system now has a ruined Mega Shipyard instead.

- Updated to 2.8.
- Supernovae now destroy all archaeological sites in the system.