Display rendered submissions in views

Thanks! This looks pretty good. I altered the code slightly to bulk load the submissions and nodes all at the same time. There's not much benefit of having the $this->submissions and $this->nodes properties if we're loading them all one at a time still. This patch bulk loads both.

The only shortcoming of this patch is that I'd like to see it printing out a title of some kind for each submission. As-is, they're all just kind of jumbled next to each other. I suppose for some use-cases, that's adequate. Anyway it's better than nothing, so committed to 7.x-4.x. Thanks!