Modify give command to support 1.7 features. Fixes BUKKIT-5286

Necessary additions include an interface to add internal value conversions
that are inappropriate for proper API design. This acts as a substitute
for properly formed, user-friendly commands in an effort to maintain
relatively vanilla behavior.

By: Wesley Wolfe <weswolf@aol.com>

paper-api/src/main/java/org/bukkit/UnsafeValues.java

@@ -0,0 +1,27 @@
+package org.bukkit;
+
+import java.util.List;
+
+import org.bukkit.inventory.ItemStack;
+
+/**
+ * This interface provides value conversions that may be specific to a
+ * runtime, or have arbitrary meaning (read: magic values).
+ * <p>
+ * Their existence and behavior is not guaranteed across future versions. They
+ * may be poorly named, throw exceptions, have misleading parameters, or any
+ * other bad programming practice.
+ * <p>
+ * This interface is unsupported and only for internal use.
+ *
+ * @deprecated Unsupported & internal use only
+ */
+@Deprecated
+public interface UnsafeValues {
+
+    Material getMaterialFromInternalName(String name);
+
+    List<String> tabCompleteInternalMaterialName(String token, List<String> completions);
+
+    ItemStack modifyItemStack(ItemStack stack, String arguments);
+}