Warn When Closing Page if Nitpick Text Not Submitted See #495

I don't do much Javascript, but thought I'd give this a shot. 

Tested in the recent versions of Firefox, Chrome and Safari (I don't have IE on my machine, so I'd need someone to verify I suppose).



Alert when you've added data to the Nitpick comment form and navigate away without saving.



edit / Ahh, dang Javascript and all those semicolons. Build passing now :)