Fixed 2 bugs:

BUG: unequipping an item will lose the item if the same item already exists in inventory
Cause: Map structure replaces existing key
Fix: Used List instead of Map

BUG: Unable to equip looted items
Cause: Weapon/Armor items are instantiated as Item object.
Fix: Weapon/Armor items are instantiated properly according to item class
Added new feature where players can press Up and Down arrow keys to retrieve 10 previous commands.
Added "loot all" feature.
Added new feature "l [argument]" which allows players to look adjacent rooms, corpse loot, and other player's equipment.