paint is never called on Wayland

[rosefromthedead]

In the shello example, the window that opens takes up the whole screen and "looks transparent" (which might just be kwin not painting anything, rather than painting full transparency). The window still receives clicks and keyboard events. render() never gets called.

[derekdreery]

Yep Wayland seems to be broken at the minute. I know that winit works reasonably well, so perhaps that would be a good start point. I would like to work on this but need to wait until I have some free time.

[DJMcNab]

Since #107, this is now resolved.
Although the actual backend still needs a lot of work - see #118