kmscube: simple example using kms+gbm

From time to time I've been getting questions about how to use gl/egl

without x11. And I would point them at Jesse's blog post:

http://virtuousgeek.org/blog/index.php/jbarnes/2011/10/31/writing_stanalone_...

But I wanted some simple example that was updated to work w/ the gbm surface stuff, instead of the surfaceless_gles2 extension, but a bit simpler than kmscon or weston. So I whipped up a simple rotating cube test:

https://github.com/robclark/kmscube git://github.com/robclark/kmscube.git

Hopefully somebody finds this useful. I've tested this on i915 and on panda (with the hopefully-soon-to-be-released pvr gbm/kms support).

BR, -R