Adding shoutbox feature for user pages and user's dashboard

@cgruppioni @chukdisc

I also know that I'm using _path for many link_tos, but those are all placeholders until I actually use them. Also, wouldn't mind tips on what I should be doing with my divs, classes and ids + css.
Totally slipped my mind. I wanted to check that the shout_sender was the current_user. That way, only the person who sent the shout is able to delete his own shout (and soon, it'll be the owner of the page, too)