On Save event

[LukeTOBrien]

Hello chaps,

I am just researching into an idea for a project I am working on.
Is it possible to attach a handler onto the save event?

AFRAME.INSPECTOR.on('save', function(event){  })

And then I would expect a JSON object with all the changes made during the inspection session, or just an HTML string of the whole scene (you currently have 'Copy to clipboard' which is great).
I am aware of the Inspector Watcher - By my project is kinda like a WYSIWYG an currently the scene is in a iFrame, so the watcher will not work in my case.

I have also seen this PR #514 but I don't know what events that exposes.

Thanks.
Luke