(IState.cs) new file.
(Miner.cs) implement ChangeState and Update.
Add state classes for class Mine.
(GoHomeAndSleepTilRested.cs) implement the all.
(EnterMineAndDigForNugget.cs) implement the all.
(VisitBankAndDepositGold.cs) implement the all.
(QuenchThirst.cs) implement the all.