message: Fixed a bug in the immigration code
diff: @@ -324,7 +324,7 @@ def updateLastTurnAlive(iPlayer, bAlive):
  def getImmigrationValue(city):
  iFoodDifference = city.foodDifference(False)
  - iHappinessDifference = city.happyLevel - city.unhappyLevel(0)
  + iHappinessDifference = city.happyLevel() - city.unhappyLevel(0)
  iValue = 0
  