Release 1.5.0 - Add appliance store, real estate, game length selection and increase max balance

A little trail of features, which have enabled each other...

• Ability to purchase real estate - the apartment, penthouse and mansion can now be purchased;
• The appliance store has been added - with the ability to purchase bed, TV and more (depending on type of property owned);
• All of this was enabled with the upgrade to a 32-bit balance value, meaning the player can now have $1B+;
• Endgame now updated to give ranks based on total balances >$65K;
• Ability to select game length - 15, 30, 100 days or unlimited

Bug fixes:

• Fix calculation of enemy health in bar fight which previously caused underflow.
• Fix bug with "cheat" entry, which caused incorrect activation of god mode cheat.