Player: new attribute 'goldAmount' (+ rendering in HUD)
GatherOrder: Player gold amount is increased when worker "touches" townhall while carrying gold
Unit: Replace SetHoldingGold() with ToggleHoldingGold()
Unit: Move EUnitState and EUnitType enumerations into 'UnitDesc'
UnitDesc: new attribute 'goldPrice'
Fixe: Bad sign in IncreaseGoldAmount()
Training unit might cost gold to player (canceling it, restore the gold spent)
Building unit might cost gold to player (canceling it, restore gold spent)
Hud: Build/train command which can't be afforded are surrounded with red square
Merge branch 'dev_gold' into develop