Use List instead of ImmutableList to allow nulls

src/main/java/com/elytradev/probe/api/IProbeData.java

@@ -1,8 +1,8 @@
 package com.elytradev.probe.api;
 
-import javax.annotation.Nonnull;
+import java.util.List;
 
-import com.google.common.collect.ImmutableList;
+import javax.annotation.Nonnull;
 
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.text.ITextComponent;
@@ -120,10 +120,10 @@ public interface IProbeData {
 	/**
 	 * Gets any inventory associated with this ProbeData. In the case where only a single itemslot is exposed, a probe
 	 * implementation may choose to enlarge the displayed item.
-	 * @return an ImmutableList containing all visible inventory slots, empty or filled, in this inventory. A probe
+	 * @return a List containing all visible inventory slots, empty or filled, in this inventory. A probe
 	 * implementation is then free to elide stacks or slots in order to present the inventory more succinctly, or
 	 * depending on its configuration.
 	 */
 	@Nonnull
-	public ImmutableList<ItemStack> getInventory();
+	public List<ItemStack> getInventory();
 }

src/main/java/com/elytradev/probe/api/impl/ProbeData.java

@@ -7,8 +7,6 @@
 
 import com.elytradev.probe.api.IProbeData;
 import com.elytradev.probe.api.IUnit;
-import com.google.common.collect.ImmutableList;
-
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.text.ITextComponent;
 import net.minecraft.util.text.TextComponentString;
@@ -19,7 +17,7 @@ public class ProbeData implements IProbeData {
 	private double barCur = Double.NaN;
 	private double barMax = Double.NaN;
 	private IUnit barUnit = null;
-	private ImmutableList<ItemStack> inventory = null;
+	private List<ItemStack> inventory = null;
 
 	/**
 	 * Creates a blank data line
@@ -83,7 +81,7 @@ public ProbeData withBar(double minimum, double current, double maximum, IUnit u
 	 * @param inventory the contents of all itemslots, full or empty, in this datum.
 	 * @return this ProbeData
 	 */
-	public ProbeData withInventory(@Nonnull ImmutableList<ItemStack> inventory) {
+	public ProbeData withInventory(@Nonnull List<ItemStack> inventory) {
 		this.inventory = inventory;
 		return this;
 	}
@@ -132,7 +130,7 @@ public boolean hasInventory() {
 
 	@Override
 	@Nullable
-	public ImmutableList<ItemStack> getInventory() {
+	public List<ItemStack> getInventory() {
 		return inventory;
 	}