Revision 647 - 2006-10-05:
Added: New database flags for modders:
TerrainImprovementDB:
HappyInc: Terrain Improvement increases happiness of its city.

Revision 567 - 2006-04-29:
Added: New database flags for modders:
ResourceDB:
HappyInc: Good increases city happiness if it is traded.

Revision 543 - 2006-02-15:
Added: New database flags for modders:
CityStyleDB:
HappyInc: City style increases city happiness.

Revision 543 - 2006-02-15:
Added: New database flags for modders:
CivilisationDB:
HappyInc: Civilisation increases city happiness.