Fixes for some things that can be null, adds functions for LearnedMove uses

PkmnLibSharp/Battling/Battle/Battle.cs

@@ -155,9 +155,9 @@ namespace PkmnLibSharp.Battling
             Creaturelib.Generated.Battle.ForceRecall(Ptr, side, index).Assert();
         }
         
-        public void SwitchPokemon(byte side, byte index, Pokemon newPokemon)
+        public void SwitchPokemon(byte side, byte index, Pokemon? newPokemon)
         {
-            Creaturelib.Generated.Battle.SwitchCreature(Ptr, side, index, newPokemon.Ptr).Assert();
+            Creaturelib.Generated.Battle.SwitchCreature(Ptr, side, index, newPokemon?.Ptr ?? IntPtr.Zero).Assert();
         }
 
         public bool CanSlotBeFilled(byte side, byte index)

PkmnLibSharp/Battling/Battle/BattleSide.cs

@@ -44,10 +44,12 @@ namespace PkmnLibSharp.Battling
             Creaturelib.Generated.BattleSide.SetCreature(Ptr, pokemon.Ptr, index);
         }
 
-        public Pokemon GetPokemon(byte index)
+        public Pokemon? GetPokemon(byte index)
         {
             var ptr = IntPtr.Zero;
             Creaturelib.Generated.BattleSide.GetCreature(ref ptr, Ptr, index);
+            if (ptr == IntPtr.Zero)
+                return null;
             if (TryResolvePointer(ptr, out Pokemon? pokemon))
                 return pokemon!;
             return Constructor.Active.ConstructPokemon(ptr)!;

PkmnLibSharp/Battling/LearnedMove.cs

@@ -42,6 +42,22 @@ namespace PkmnLibSharp.Battling
 
         private MoveData? _move;
 
+        public void DecreaseUses(byte amount)
+        {
+            LearnedAttack.DecreaseUses(Ptr, amount);
+        }
+        
+        public void RestoreUses(byte amount)
+        {
+            LearnedAttack.RestoreUses(Ptr, amount);
+        }
+        
+        public void RestoreAllUses()
+        {
+            LearnedAttack.RestoreAllUses(Ptr);
+        }
+
+
         public override string ToString()
         {
             return base.ToString() + $": {Move.Name} PP: {RemainingUses}/{MaxUses}";

PkmnLibSharp/Battling/Pokemon.cs

@@ -31,7 +31,7 @@ namespace PkmnLibSharp.Battling
 
         protected static IntPtr CreatePtr(BattleLibrary library, Species species, Forme forme, byte level,
             uint experience, uint uid, Gender gender, byte coloring, Item? heldItem, string? nickname,
-            bool hiddenAbility, byte abilityIndex, IReadOnlyCollection<LearnedMove> moves, StatisticSet<byte> ivs,
+            bool hiddenAbility, byte abilityIndex, IReadOnlyCollection<LearnedMove?> moves, StatisticSet<byte> ivs,
             StatisticSet<byte> evs, Nature nature, bool allowedExperienceGain, bool isEgg)
         {
             var movesArr = moves.Select(x => x?.Ptr ?? IntPtr.Zero).ToArray();