Hot reloading support

Good morning,

I was just asking if hot reloading is supposed to work, because when I open the platformer demo and try to change the script and save the simulation stops.

Thanks

首先在 platformer demo 中复现该问题：编辑脚本，保存脚本，并观察模拟停止。跟踪 JavaScript binding 的 hot-reloading 路径，并将完成定义为：保存脚本不再导致模拟停止，并且在 demo 运行期间应用更改。

由索引模型根据 Issue 内容生成。