Python: Add TurboGears templating example

Author: RasmusWL

python/ql/test/library-tests/web/turbogears/Controller.expected

@@ -2,3 +2,4 @@
 | test.py:13:5:13:50 | Function ok_validated |
 | test.py:18:5:18:57 | Function partially_validated |
 | test.py:22:5:22:51 | Function not_validated |
+| test.py:26:5:26:28 | Function with_template |

python/ql/test/library-tests/web/turbogears/Sinks.expected

@@ -2,3 +2,4 @@
 | test.py:14 | BinaryExpr | externally controlled string |
 | test.py:19 | BinaryExpr | externally controlled string |
 | test.py:23 | BinaryExpr | externally controlled string |
+| test.py:27 | Dict | {externally controlled string} |

python/ql/test/library-tests/web/turbogears/test.py

@@ -21,3 +21,7 @@ def partially_validated(self, a=None, b=None, *args):
     @expose()
     def not_validated(self, a=None, b=None, *args):
         return 'Values: %s, %s, %s' % (a, b, args)
+
+    @expose("<template_path>")
+    def with_template(self):
+        return {'template_var': 'foo'}