forgot to convert some 'alliance' variable to 'finalAlliance' variable (when signing mutual peace between alliance members)

Fixed: non-alliance members no longer sign peace with alliance members at the time of alliance creation.

- NPC faction with 0 settlement can rebel against one of dominant factions, having 40% chance to overthrow each of oppressor's settlement. Exclusive to distance-based conquest option.
- Enable 'History Generation' as permanent game condition on scenario setting to start the game on world where major wars have already happened, instead of default one where every faction have even distribution.
- Alliance join chance reduced from 90% to 80%

Fix: number of total settlements were including ones not eligible for conquest, such as player colonies and RimCities.
Alliance threshold is now 40~60%.

Changed alliance condition threshold to 40~70% dominance.

Made alliance event optional.
Decreased alliance condition to 40% dominance.

Added detailed description to mod settings.
Added alliance event.

[Auto-generated text]: Update on 2/28/2020 3:18:39 AM.

[Auto-generated text]: Update on 2/27/2020 6:34:02 PM.

[Auto-generated text]: Update on 2/27/2020 6:15:01 PM.