add Kontalk messenger

README.md

@@ -100,6 +100,7 @@ Table of Contents
   * [Node-Chat](https://github.com/IgorAntun/node-chat) - A not-so-basic open-source chat with admin features. - `MIT`
   * [Prosody](http://prosody.im/) – Modern XMPP server written in Lua.
   * [Kandan](http://getkandan.com/) – Kandan is an Open Source Alternative to HipChat. - `GNU-AGPL`
+  * [Kontalk](http://kontalk.org/) – Kontalk is an Open Source Messenger, similiar to WhatsApp (app for android only currently), including end-to-end encryption, server is based on Tigase XMPP Server - [Source code](https://github.com/kontalk)) - `GPLv3`
   * [Rocket.Chat](http://rocket.chat/) – Teamchat solution similar to Gitter.im or Slack - `MIT`
   * [Kaiwa](http://getkaiwa.com) A modern XMPP Web client ([Source code](https://github.com/digicoop/kaiwa))
   * [Shout](http://shout-irc.com/) -The self-hosted web IRC client ([Demo](http://demo.shout-irc.com/), [Source code](https://github.com/erming/shout)) `MIT` `Nodejs`