Set max width on title and body content

This is a great extension, thanks! Just what I've been looking for. Only one issue for me - it doesn't fix the worst thing about the standard Wikipedia UI - the fluid body container which creates a hugely wide text column on desktop screens and makes it hard to read the text. I've added a max-width on the body and title divs to fix it on article pages.
My apologies Josselin! Now corrected.