Added functions to check if the turn can end and as a hook for when the turn actually does end.
Removed redundant info in SuperJeep.
Added a basic air unit and fighter (no special behaviour yet aside from drawing on a higher layer).
Added fuel to air units.
Added the aircraft carrier.
Aircraft now have to dock or move to advance the turn, and can refuel at carriers.
Added a function to determine whether a unit can stop in a given tile.
Aircraft now have to move a minimum distance now (though they can violate the rule to dock on a carrier).
Moved some stats to the fighter class and tweaked them.
Added the carrier class. Oops.
Added antiair unit.
Added get defense method.
Overrode superclass defense method and range method.
Made the get damage method use the new get defense method.
Buffed the anti-air's bonus, but also gave it the same terrain costs as the artillery. Switched its check for air units to a more general isinstance check.
Added detailed docstrings to every unit class.
Fixed a comment in AA which said it does bonus damage against armour.
Added team 1 fighter to island.
Added bonus damage to fighters against other air units.
Renamed "is_adj_to_carrier" to "is_docked." Changed it to a non-static method so we can check the
current unit's team. Now you can't dock at the other team's carrier.