Fixed FindFunction() to search namespaces.

src/AST/Namespace.cs

@@ -165,6 +165,11 @@ namespace CppSharp.AST
         }
 
         public Function FindFunction(string name, bool createDecl = false)
+        {
+            var entries = name.Split(new string[] { "::" },
+                StringSplitOptions.RemoveEmptyEntries).ToList();
+
+            if (entries.Count <= 1)
             {
                 var function = Functions.Find(e => e.Name.Equals(name));
 
@@ -177,6 +182,16 @@ namespace CppSharp.AST
                 return function;
             }
 
+            var funcName = entries[entries.Count - 1];
+            var namespaces = entries.Take(entries.Count - 1);
+
+            var @namespace = FindNamespace(namespaces);
+            if (@namespace == null)
+                return null;
+
+            return @namespace.FindFunction(funcName, createDecl);
+        }
+
         Class CreateClass(string name, bool isComplete)
         {
             var  @class = new Class