Support for swapping two creatures on a side.

Signed-off-by: Deukhoofd <Deukhoofd@gmail.com>

src/Battling/Models/BattleSide.hpp

@@ -85,6 +85,8 @@ namespace CreatureLib::Battling {
         void MarkAsFled() noexcept { _hasFled = true; }
 
         uint8_t GetRandomCreatureIndex();
+
+        bool SwapPositions(u8 a, u8 b);
     };
 }