Create game examples

[hecrj]

It would be great to create some actual game examples to showcase the engine as a whole. It should also help us understand the shortcomings of the engine and serve us to choose what to improve next!

The examples should be simple, so we shouldn't go too crazy with the game complexity. I think simple games like tetris, breakout, pong, etc., are the way to go. We can use OpenGameArt.org for any assets we need and give proper credits in the examples README!

This is the perfect chance if you want to get familiar with the engine while contributing at the same time!

[JohnDoneth]

I've previously started a breakout example in my fork under the branch breakout-example. I've been busy as of recently and haven't had much time to work on finishing it up. Any PR's are welcome.