Memory is not released after a scene is removed from DOM.

• A-Frame Version: 0.7.0
• Platform / Device: iPad/iPhone
• Reproducible Code Snippet or URL: https://codepen.io/ebhoren/pen/zEjYRO

Make a memory snapshot before adding a scene.
Another memory snapshot after adding a scene.
Remove the scene and take another memory snapshot.

You will see the memory is not released and just keep increasing each time you remove a scene and add a new one.

Thanks