Refactor TableView styling API

We don't want to directly expose the item properties in
the namespace of the loader. Instead we standardize on
styleData as a property container.

Change-Id: Ib451e06ab393ba4945c96076d71dd3f96489e0c7
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>
Rename controlState to styleData

Change-Id: I06c9f4b0d9b6eef7d2ca608827eee982d8d97027
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
TabViewStyle: rename 'tab' grouped property to 'styleData'

Change-Id: If56b5ca4af119d7897425609dcaf04336f77e032
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>