remove hardcoded number/assumption from filter bar layout code
Begin loading LabsListVC data in -[ viewDidLoad], not -[ viewWillAppear:]
Set LabsListVC title in init, not -[ viewDidLoad]
Be more intelligent about showing/hiding filter bar on LabsListVC

closes issue #11 - the list will not scroll every time the user
comes back to it, so their place is not lost

Also adds the nice "magnetism" effect Apple adds to UISearchBars
by default in iOS 6 when they're contained in UITableViews