ItemList refactoring

Splitted the ItemList and MeaningfulIterator into an item and fluid
version.
Added an IdentityHashMap as additional item layer to the ItemList for a
faster access.
Refactored FluidList, findFuzzy will now return the same fluid instead of
an empty collection.

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

@@ -0,0 +1,96 @@
+/*
+ * This file is part of Applied Energistics 2.
+ * Copyright (c) 2013 - 2015, 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.Iterator;
+import java.util.NavigableMap;
+import java.util.NoSuchElementException;
+
+import appeng.api.storage.data.IAEItemStack;
+
+
+public class MeaningfulItemIterator<T extends IAEItemStack> implements Iterator<T>
+{
+
+	private final Iterator<NavigableMap<T, T>> parent;
+	private Iterator<T> innerIterater = null;
+	private T next;
+
+	public MeaningfulItemIterator( Iterator<NavigableMap<T, T>> iterator )
+	{
+		this.parent = iterator;
+
+		if( this.parent.hasNext() )
+		{
+			this.innerIterater = this.parent.next().values().iterator();
+		}
+	}
+
+	@Override
+	public boolean hasNext()
+	{
+		if( this.innerIterater == null )
+		{
+			return false;
+		}
+
+		while( this.innerIterater.hasNext() || this.parent.hasNext() )
+		{
+			if( this.innerIterater.hasNext() )
+			{
+				this.next = this.innerIterater.next();
+
+				if( this.next.isMeaningful() )
+				{
+					return true;
+				}
+				else
+				{
+					this.innerIterater.remove(); // self cleaning :3
+				}
+			}
+
+			if( this.parent.hasNext() )
+			{
+				this.innerIterater = this.parent.next().values().iterator();
+			}
+		}
+
+		this.next = null;
+		return false;
+	}
+
+	@Override
+	public T next()
+	{
+		if( this.next == null )
+		{
+			throw new NoSuchElementException();
+		}
+
+		return this.next;
+	}
+
+	@Override
+	public void remove()
+	{
+		this.parent.remove();
+	}
+}