Strategy Tweaks

After many pages of discussions, it's been decided to implement the following tweaks to strategies, in order to improve their balance:

Iron Fist: Reduced the Air/Naval Transports' -3 range nerf to -2.
Great Combinator: Reduced the -3 defense/attack nerf for Infantry and Tanks to -2.
Relentless Attack: Reduced Tanks cost by 10.
Hybrid Warfare: Removed the Air/Naval Transport nerfs and reduced Infantry cost by 15.
All: Removed the -2 defense for Helicopters against Bombers.