Add layout-view.jsdoc

I took **TONS** of liberty with this doc, so you'll want to review this to make sure you're ok with it. 

I added a `events` section, so please check and see if I have that part correct as well since it's just based on reading the code (I haven't actually used the events cb like that before)

I'll also review it again later on in the week 'cuz I can't look @ it anymore.
Thanks for adding this. We'll have to find a way to put that into www. Generally custom fields make a lot of sense.