Enhance docu about _upsertBindings()

[DoomyTheFroomy]

After #105 has been successfully solved it is necessary to call this._upsertBindings() in the render function. Otherwise the view won't be rendered correctly after it has been removed. This happens mostly if you use a ampersand-view-switcher to handle your workflow and you have overridden the render function to do your own stuff. A better solution would be to generally call this._upsertBindings(), when render() is called, even if it is overridden.

[cdaringe]

Ah, difficult to believe this hasn't come up before. I thought we handled this case? Checkout _setRender. When you extend the view, we wrap it, call your new render, and do some other work. We could probably find a way in there to do the upsert in there and make you never have to worry about it. What do you think?

[DoomyTheFroomy]

@cdaringe this sounds good and looks like the right place, the same would be for _setRemove!
I think you didn't came up before, because this case is very special, but if you like I could give you an example?!

[cmazakas]

I've had many issues with bindings in Ampersand. I've actually kind of just started writing my own bindings manually.

[wraithgar]

I believe once this PR is merged it will solve this issue #181