debian/copyright: Add MIT license details

debian/copyright

@@ -3,8 +3,12 @@ Upstream-Name: node-websocket
 Upstream-Contact: Brian McKelvey <theturtle32@gmail.com>
 Source: https://github.com/theturtle32/WebSocket-Node
 
+Files: lib/BufferUtil.fallback.js lib/BufferUtil.js lib/Validation.fallback.js lib/Validation.js src/bufferutil.cc src/validation.cc
+Copyright: 2011, Einar Otto Stangvik <einaros@gmail.com>
+License: MIT
+
 Files: *
-Copyright: 2010-2015, Copyright 2010-2015 Brian McKelvey
+Copyright: 2010-2015, Brian McKelvey
 License: Apache-2.0
 
 Files: debian/*
@@ -15,3 +19,22 @@ License: Apache-2.0
  The Apache-2.0 license can be found in /usr/share/common-licenses/Apache-2.0
  on your Debian system.
 
+License: MIT
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ 'Software'), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+ .
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+ .
+ THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.