Added an helper method to get the type map of a declaration.

src/Generator/Types/TypeMap.cs

@@ -8,6 +8,7 @@ namespace Cxxi.Types
     {
         public string ArgName { get; set; }
         public string ReturnVarName { get; set; }
+        public Type ReturnType { get; set; }
         public Parameter Parameter { get; set; }
     }
 
@@ -99,6 +100,11 @@ namespace Cxxi.Types
             }
         }
 
+        public bool FindTypeMap(Declaration decl, out TypeMap typeMap)
+        {
+            return FindTypeMap(decl.QualifiedOriginalName, out typeMap);
+        }
+
         public bool FindTypeMap(string name, out TypeMap typeMap)
         {
             System.Type type;