licenses: Add tornado license information.

We are using a modified version of some code which originates from
the tornado web server project. Therfore we include the original license
information in our project to comply to the license.

licenses/tornado_license.txt

@@ -0,0 +1,13 b''
+# Copyright 2009 Facebook
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.

LICENSE.txt

@@ -10,8 +10,10 b' permission notice:'
        file:
    Copyright (c) 2008-2011 - msgpack-python
        file:licenses/msgpack_license.txt
+   Copyright (c) 2009 - tornado
+       file:licenses/tornado_license.txt
 
-Both licensed under the Apache License, Version 2.0 (the "License");
+All licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at