message: Caravel also upgrades to Torpedo Boat
diff: <UnitClassUpgradeType>UNITCLASS_FRIGATE</UnitClassUpgradeType>
  <bUnitClassUpgrade>1</bUnitClassUpgrade>
  </UnitClassUpgrade>
  + <UnitClassUpgrade>
  + <UnitClassUpgradeType>UNITCLASS_TORPEDO_BOAT</UnitClassUpgradeType>
  + <bUnitClassUpgrade>1</bUnitClassUpgrade>
  + </UnitClassUpgrade>
  </UnitClassUpgrades>
  <UnitAIs>
  <UnitAI>
  <UnitClassUpgradeType>UNITCLASS_FRIGATE</UnitClassUpgradeType>
  <bUnitClassUpgrade>1</bUnitClassUpgrade>
  </UnitClassUpgrade>
  + <UnitClassUpgrade>
  + <UnitClassUpgradeType>UNITCLASS_TORPEDO_BOAT</UnitClassUpgradeType>
  + <bUnitClassUpgrade>1</bUnitClassUpgrade>
  + </UnitClassUpgrade>
  </UnitClassUpgrades>
  <UnitAIs>
  <UnitAI>
  <UnitClassUpgradeType>UNITCLASS_FRIGATE</UnitClassUpgradeType>
  <bUnitClassUpgrade>1</bUnitClassUpgrade>
  </UnitClassUpgrade>
  + <UnitClassUpgrade>
  + <UnitClassUpgradeType>UNITCLASS_TORPEDO_BOAT</UnitClassUpgradeType>
  + <bUnitClassUpgrade>1</bUnitClassUpgrade>
  + </UnitClassUpgrade>
  </UnitClassUpgrades>
  <UnitAIs>
  <UnitAI>
  