message: Increase Levee cost to 250
diff: <ArtDefineTag>ART_DEF_BUILDING_LEVEE</ArtDefineTag>
  <PrereqTech>TECH_HYDRAULICS</PrereqTech>
  <bRiver>1</bRiver>
  - <iCost>180</iCost>
  + <iCost>250</iCost>
  <iAdvancedStartCost>100</iAdvancedStartCost>
  <iMinAreaSize>-1</iMinAreaSize>
  <iConquestProb>66</iConquestProb>
  <PrereqTech>TECH_HYDRAULICS</PrereqTech>
  <bWater>1</bWater>
  <bRiver>1</bRiver>
  - <iCost>180</iCost>
  + <iCost>200</iCost>
  <iAdvancedStartCost>100</iAdvancedStartCost>
  <iMinAreaSize>-1</iMinAreaSize>
  <iConquestProb>66</iConquestProb>
  