[Bleeding] Fix some inventories not using maxStack. Fixes BUKKIT-2883

CraftBukkit adds the ability to specify the maxStack size for most
inventories. However, some inventories were not overriding the getMaxStack
method properly, and so the functionality was unavailable. This fixes the
maxStack setting for Anvils, Minecarts, PlayerInventory, and Hoppers.

src/main/java/net/minecraft/server/ContainerAnvilInventory.java

@@ -46,6 +46,12 @@ public class ContainerAnvilInventory extends InventorySubcontainer { // CraftBuk
         this.setMaxStackSize(1); // CraftBukkit
     }
 
+    // CraftBukkit start - override inherited maxStack from InventorySubcontainer
+    public int getMaxStackSize() {
+        return maxStack;
+    }
+    // CraftBukkit end
+
     public void update() {
         super.update();
         this.a.a((IInventory) this);

src/main/java/net/minecraft/server/EntityMinecartContainer.java

@@ -145,7 +145,7 @@ public abstract class EntityMinecartContainer extends EntityMinecartAbstract imp
     }
 
     public int getMaxStackSize() {
-        return 64;
+        return maxStack; // CraftBukkit
     }
 
     public void b(int i) {

src/main/java/net/minecraft/server/PlayerInventory.java

@@ -411,7 +411,7 @@ public class PlayerInventory implements IInventory {
     }
 
     public int getMaxStackSize() {
-        return 64;
+        return maxStack; // CraftBukkit
     }
 
     public boolean b(Block block) {

src/main/java/net/minecraft/server/TileEntityHopper.java

@@ -150,7 +150,7 @@ public class TileEntityHopper extends TileEntity implements IHopper {
     }
 
     public int getMaxStackSize() {
-        return 64;
+        return maxStack; // CraftBukkit
     }
 
     public boolean a(EntityHuman entityhuman) {