Refactored AEStacks & ItemList (#4406)

Removed custom VarInt/VarLong solution.
Moved itemstack and fluidstack serialisation to their own NBT tag to avoid interference.
Removed now useless NBT sorting
Added NullItemList

src/main/java/appeng/util/item/NullItemList.java

@@ -0,0 +1,95 @@
+/*
+ * This file is part of Applied Energistics 2.
+ * Copyright (c) 2013 - 2020, AlgorithmX2, All rights reserved.
+ *
+ * Applied Energistics 2 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Applied Energistics 2 is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Applied Energistics 2.  If not, see <http://www.gnu.org/licenses/lgpl>.
+ */
+
+package appeng.util.item;
+
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+
+import appeng.api.config.FuzzyMode;
+import appeng.api.storage.data.IAEItemStack;
+import appeng.api.storage.data.IItemList;
+
+
+public class NullItemList implements IItemList<IAEItemStack>
+{
+
+	@Override
+	public void add( IAEItemStack option )
+	{
+	}
+
+	@Override
+	public IAEItemStack findPrecise( IAEItemStack i )
+	{
+		return null;
+	}
+
+	@Override
+	public Collection<IAEItemStack> findFuzzy( IAEItemStack input, FuzzyMode fuzzy )
+	{
+		return Collections.emptyList();
+	}
+
+	@Override
+	public boolean isEmpty()
+	{
+		return true;
+	}
+
+	@Override
+	public void addStorage( IAEItemStack option )
+	{
+	}
+
+	@Override
+	public void addCrafting( IAEItemStack option )
+	{
+	}
+
+	@Override
+	public void addRequestable( IAEItemStack option )
+	{
+	}
+
+	@Override
+	public IAEItemStack getFirstItem()
+	{
+		return null;
+	}
+
+	@Override
+	public int size()
+	{
+		return 0;
+	}
+
+	@Override
+	public Iterator<IAEItemStack> iterator()
+	{
+		return Collections.emptyIterator();
+	}
+
+	@Override
+	public void resetStatus()
+	{
+	}
+
+}