Add std_auto_ptr.i defining typemaps for returning std::auto_ptr<>.

These typemaps are currently defined for C#, Java and Python only and the
tests are provided only for these languages.

Also add a brief description of the new header to the documentation.

Examples/test-suite/csharp/li_std_auto_ptr_runme.cs

@@ -0,0 +1,37 @@
+using System;
+using li_std_auto_ptrNamespace;
+
+public class li_std_auto_ptr_runme {
+    private static void WaitForGC()
+    {
+        System.GC.Collect(); 
+        System.GC.WaitForPendingFinalizers();
+        System.Threading.Thread.Sleep(10);
+    }
+
+    public static void Main()
+    {
+        Klass k1 = li_std_auto_ptr.makeKlassAutoPtr("first");
+        if (k1.getLabel() != "first")
+            throw new Exception("wrong object label");
+
+        Klass k2 = li_std_auto_ptr.makeKlassAutoPtr("second");
+        if (Klass.getTotal_count() != 2)
+            throw new Exception("number of objects should be 2");
+
+        k1 = null;
+        WaitForGC();
+
+        if (Klass.getTotal_count() != 1)
+            throw new Exception("number of objects should be 1");
+
+        if (k2.getLabel() != "second")
+            throw new Exception("wrong object label");
+
+        k2 = null;
+        WaitForGC();
+
+        if (Klass.getTotal_count() != 0)
+            throw new Exception("no objects should be left");
+    }
+}