X11 support for Haiku

[lelldorin]

@extrowerk

Just look at the comment from @lelldorin : is it really the Haiku way if we have to write a tutorial how to start a gui program?

1. I does not know thst it is a gui program.
2. If you have haiku specific tutorials around, displayed by searching, this makes haiku present
3. Not ever gui app are self explaining
4. The most haiku apps are without docs