Game rules:
 * When a tile with the HQ tag is captured, the team that owned that property
   loses and all of their property goes to the captor.
 * Units can combine to raise their HP up to 100%
 * Units can now be recovered by resting on properties. Properties that recover
   forfeit their income for that turn.
 * Units can now be loaded and unloaded. A unit can unload all of its carryons
   in one turn.
Made failing tests work again
 * Started counting days at 1
 * Use a dictionary for the grid instead of an array