Fluid cleanup and performance improvements (#3581)

Use custom gui widget with custom synchronization for rendering fake fluid slots.

src/main/java/appeng/fluids/util/AEFluidTank.java

@@ -0,0 +1,79 @@
+/*
+ * This file is part of Applied Energistics 2.
+ * Copyright (c) 2013 - 2018, 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.fluids.util;
+
+
+import net.minecraft.tileentity.TileEntity;
+import net.minecraftforge.fluids.FluidTank;
+
+import appeng.api.storage.data.IAEFluidStack;
+import appeng.util.Platform;
+
+
+public class AEFluidTank extends FluidTank implements IAEFluidTank
+{
+	private final IAEFluidInventory host;
+
+	public AEFluidTank( IAEFluidInventory host, int capacity )
+	{
+		super( capacity );
+		this.host = host;
+		if (host instanceof TileEntity)
+		{
+			this.setTileEntity( (TileEntity) host );
+		}
+	}
+
+	@Override
+	protected void onContentsChanged()
+	{
+		if( host != null && Platform.isServer() )
+		{
+			host.onFluidInventoryChanged( this, 0 );
+		}
+		super.onContentsChanged();
+	}
+
+	@Override
+	public void setFluidInSlot( int slot, IAEFluidStack fluid )
+	{
+		if( slot == 0 )
+		{
+			this.setFluid( fluid == null ? null : fluid.getFluidStack() );
+			this.onContentsChanged();
+		}
+	}
+
+	@Override
+	public IAEFluidStack getFluidInSlot( int slot )
+	{
+		if( slot == 0 )
+		{
+			return AEFluidStack.fromFluidStack( this.getFluid() );
+		}
+		return null;
+	}
+
+	@Override
+	public int getSlots()
+	{
+		return 1;
+	}
+
+}