Copyright for python-tornado4 source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: Tornado
Upstream-Contact: python-tornado@googlegroups.com
Source: http://www.tornadoweb.org/

Files: *
Copyright: 2009-2014 Facebook
License: Apache-2.0

Files: tornado/locks.py tornado/queues.py tornado/routing.py
Copyright: 2015 The Tornado Authors
License: Apache-2.0

Files: tornado/websocket.py
Copyright: 2010 Jacob Kristhammar
License: Apache-2.0

Files: tornado/test/twisted_test.py
Copyright: 2011 Ovidiu Predescu
License: Apache-2.0

Files: demos/chat/static/chat.js
 demos/chat/static/chat.css
 demos/blog/schema.sql
 demos/websocket/static/chat.js
 demos/websocket/static/chat.css
Copyright: 2009 FriendFeed
License: Apache-2.0

Files: debian/*
Copyright: 2010, 2011 Carl Chenet 
 2011 Yaroslav Halchenko
 2012 Thomas Kluyver
 2012 Julian Taylor
 2015 Julien Puydt
 2016-2018 Ondřej Nový 
License: Apache-2.0

License: Apache-2.0
 Licensed to the Apache Software Foundation (ASF) under one or more contributor
 license agreements. The ASF licenses this work to You under the Apache License,
 Version 2.0 (the "License"); you may not use this work except in compliance
 with the License.  You may obtain a copy of the License at
 .
     http://www.apache.org/licenses/LICENSE-2.0
 .
 On a Debian system, the license can be found at
 /usr/share/common-licenses/Apache-2.0 .