Added license header to std_name_table.py

Author: larsbarring

lib/iris/std_name_table.py

@@ -1,3 +1,12 @@
+# Copyright Iris contributors
+#
+# This file is part of Iris and is released under the LGPL license.
+# See COPYING and COPYING.LESSER in the root of the repository for full
+# licensing details.
+"""
+Handling of standard names and standard name aliases.
+"""
+
 import warnings
 
 import iris.std_names