Preliminary JSON for breakout is finished.

Here's the JSON for breakout. It's long, but take note of the following parts:

- The "Disappearable" trait, it's right at the top.
- The text node object (search for "score"), where we added a new physics_type ("none") and a "type" so we can differentiate between text and sprite nodes

Everything else is auto-generated and pretty much the same as pong.json. @abutterf If you can double-check the language grammar inside Disappearable and the text node. Everyone else, please take a look so you know what we have to support for breakout and can plan your work accordingly.