Better handling of filling empty slots.

src/Battling/Models/CreatureIndex.hpp

@@ -15,6 +15,10 @@ namespace CreatureLib::Battling {
         uint8_t GetSideIndex() const { return _side; }
 
         uint8_t GetCreatureIndex() const { return _creature; }
+
+        bool operator==(const CreatureIndex& rhs) const { return (_side == rhs._side) && (_creature == rhs._creature); }
+
+        bool operator!=(const CreatureIndex& rhs) const { return !operator==(rhs); }
     };
 }