added unbound to external deps

external/unbound/libunbound/python/doc/examples/example7.rst

@@ -0,0 +1,18 @@
+.. _example_idna:
+
+=================================================
+Internationalized domain name support
+=================================================
+
+Unlike the libUnbound, pyUnbound is able to handle IDN queries.
+
+..	literalinclude:: example7-1.py
+	:language: python
+
+If we use unicode string in :meth:`unbound.ub_ctx.resolve` method, the IDN DNAME conversion (if it is necessary) is performed on background.
+
+..	literalinclude:: example7-2.py
+	:language: python
+
+The :class:`unbound.ub_data` class contains attributes suffix which converts the dname to UTF string. These attributes have the '_idn' suffix.
+Apart from this aproach, two conversion functions exist (:func:`unbound.idn2dname` and :func:`unbound.dname2idn`).