add licence information for otr.js and dependencies

README

@@ -96,7 +96,7 @@ A big big thank to the authors/contributors of...
 
 proxy65:
 SàT (plugin_xep_0065) use nearly all the code from proxy65 (http://code.google.com/p/proxy65/) which was coded by Dave Smith (2002-2004) and maintained by Fabio Forno (2007-2008).
-As the original MIT licence allow, the code is reused and sub-licenced until GPL v3 to follow the rest of the code.
+As the original MIT licence allows, the code is reused and sub-licenced until GPL v3 to follow the rest of the code.
 
 progressbar:
 SàT (jp) use ProgressBar (http://pypi.python.org/pypi/progressbar/2.2), a class coded by Nilton Volpato which allow the textual representation of progression.
@@ -125,6 +125,14 @@ Libervia use txJSON-RPC (https://launchpad.net/txjsonrpc), a twisted library to
 Mutagen:
 Mutagen (https://code.google.com/p/mutagen/) is an audio metadata handling library, it's use by the radiocol plugin.
 
+otr.js and its dependencies Big Integer Library, CryptoJS, EventEmitter:
+Libervia frontend uses otr.js and its dependencies:
+    - otr.js was coded by Arlo Breault (2014) and is released under the Mozilla Public License Version 2.0
+    - Big Integer Library was coded by Leemon Baird (2000-2013) and is in the public domain
+    - CryptoJS was coded by Jeff Mott (2009-2013) and is released under the MIT licence
+    - EventEmitter was coded by Oliver Caldwell (2011-2013) and is released under the MIT licence
+As the original licences allow, the code is reused and sub-licenced until GPL v3 to follow the rest of the code.
+
 pictures found in frontends/src/wix/images/crystal/:
 These pictures come from Crystal clear, were made by Everaldo Coelho (www.everaldo.com) and YellowIcon (www.yellowicon.com). They are under LGPL V3 licence (see frontends/src/wix/images/COPYING.LESSER).
 Found on http://commons.wikimedia.org/wiki/File:Crystal_Clear_app_browser.png and http://commons.wikimedia.org/wiki/File:Crystal_Clear_app_cache.png