Getting close to implementing serialization and deserialization

[gusmccallum]

Load and save methods added for:

• Entity -> this seems to fail when saving
• Engine
• Map
• Level
• Room
• Tile
• TCODColor
• Container
• Attacker
• Destructible
• Use

As well as load_and_construct methods where appropriate

• Polymorphic Type Registration for MonsterDestructible WIP
• Added cereal as a dependency in vcpkg.json