Allow to see youtube videos in KMess

[ruben]

[18:38:37] <ahmed-tux> it is , to add youtuve html code in chat window for watching the video in chat window no need to open browser
[18:39:30] <ahmed-tux> Ruben: for example if someone send us video no need to open browser just from kmess chat window

The idea is that we allow users to watch youtube movies (and maybe other services) directly in the chatwindow. It is probably fairly simple to make, but is a nice extra. We can just add a button to show the video+some javascript to actually do it. The HTML renderer does the rest for us :)

(this nice idea comes from ahmed-tux on the IRC channel)