Added missing class TypeReference.

Should have been added back in b91ac99576.

src/AST/Reference.cs

@@ -0,0 +1,20 @@
+
+namespace CppSharp.AST
+{
+    /// <summary>
+    /// Represents a type reference.
+    /// </summary>
+    public class TypeReference
+    {
+        public Declaration Declaration;
+        public string FowardReference;
+
+        public override string ToString()
+        {
+            if (!string.IsNullOrWhiteSpace(FowardReference))
+                return FowardReference;
+
+            return base.ToString();
+        }
+    }
+}