SERIES PREMIERE: This new British import is another example of TV’s current fixation with single-crime limited series and extended stories, a mini-genre that, in essence, also includes Top of the Lake, The Killing and The Bridge. What distinguishes Broadchurch, initially, isn’t its plot or the way it’s unfurled. It’s the photography (one early shot is a very extended, complicated tracking shot, following a character as he walks through much of his small town and interacts