Refresh the history window when any scene is closed

[Sirrah]

I just saw your post about this plugin on Twitter. It works great!

This small addition refreshes the history when a scene is closed. Depending on your workflow it might not make much difference. But if you regularly load and unload additive scenes it will help keep the history clear.

I haven't gone in-depth on how the refresh works. There might be a better way to remove only the elements from the closed scene.

[adamgryu]

Thanks for this, I'll pull this in my update branch and test it out!