Re-enabled custom dispenser behavior and added a convenience registration function for it.

src/main/java/appeng/bootstrap/IItemBuilder.java

@@ -2,8 +2,10 @@ package appeng.bootstrap;
 
 
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 import net.minecraft.creativetab.CreativeTabs;
+import net.minecraft.dispenser.IBehaviorDispenseItem;
 import net.minecraft.item.Item;
 
 import appeng.core.features.AEFeature;
@@ -31,5 +33,10 @@ public interface IItemBuilder
 
 	IItemBuilder rendering( ItemRenderingCustomizer callback );
 
+	/**
+	 * Registers a custom dispenser behavior for this item.
+	 */
+	IItemBuilder dispenserBehavior( Supplier<IBehaviorDispenseItem> behavior );
+
 	ItemDefinition build();
 }