Replaced all instances of Guava's Optional type with Java 8's Optional type, as discussed in #81. (#90)

src/api/java/appeng/api/config/Upgrades.java

@@ -27,8 +27,6 @@ package appeng.api.config;
 import java.util.HashMap;
 import java.util.Map;
 
-import com.google.common.base.Optional;
-
 import net.minecraft.item.ItemStack;
 
 import appeng.api.definitions.IItemDefinition;
@@ -70,11 +68,7 @@ public enum Upgrades
 	 */
 	public void registerItem( final IItemDefinition item, final int maxSupported )
 	{
-		final Optional<ItemStack> maybeStack = item.maybeStack( 1 );
-		for( final ItemStack stack : maybeStack.asSet() )
-		{
-			this.registerItem( stack, maxSupported );
-		}
+		item.maybeStack( 1 ).ifPresent( is -> this.registerItem( is, maxSupported ) );
 	}
 
 	/**

src/api/java/appeng/api/definitions/IBlockDefinition.java

@@ -2,7 +2,7 @@
 package appeng.api.definitions;
 
 
-import com.google.common.base.Optional;
+import java.util.Optional;
 
 import net.minecraft.block.Block;
 import net.minecraft.item.ItemBlock;

src/api/java/appeng/api/definitions/IItemDefinition.java

@@ -26,7 +26,7 @@ package appeng.api.definitions;
 
 import javax.annotation.Nonnull;
 
-import com.google.common.base.Optional;
+import java.util.Optional;
 
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;

src/api/java/appeng/api/definitions/ITileDefinition.java

@@ -2,7 +2,7 @@
 package appeng.api.definitions;
 
 
-import com.google.common.base.Optional;
+import java.util.Optional;
 
 import net.minecraft.tileentity.TileEntity;
 

src/api/java/appeng/api/features/IInscriberRecipe.java

@@ -6,7 +6,7 @@ import java.util.List;
 
 import javax.annotation.Nonnull;
 
-import com.google.common.base.Optional;
+import java.util.Optional;
 
 import net.minecraft.item.ItemStack;