Validate Irrigation / Mining / Road / Railroad turn count vs Original CIV

[fire-eggs]

SWY1985 had implemented IrrigationCost and MiningCost members in the ITile classes [i.e. how many turns were required to perform that task on that terrain type]. I added RoadCost and RailroadCost to correspond.

However, I did note that several IrrigationCost values were incorrect. Need to verify all these values against Original CIV.

[axx0]

The irrigation costs (turns):

• grassland = 4
• forest = 4 (convert to plains)
• swamp = 14 (convert to grassland)
• tundra = --
• plains = 4
• jungle = 14 (convert to grassland)
• hills = 9
• mountains = --
• desert = 4
• arctic = --

Mining costs (turns):

• grassland = 9 (turn into forest)
• forest = --
• swamp = --
• tundra = --
• plains = 14 (convert to forest)
• jungle = --
• hills = 9
• mountains = 9
• desert = 5
• arctic = --