ScrollView: take Flickable::originX and originY into account

Change-Id: I16eb186a2b1f706bbc961d34a614bf2f9a9a0646
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Doc: Add a section for Styles

Change-Id: I96af8ea444754e7c3cab954622d0f385b75f9689
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>