Bug 916010 - [Contacts] Follow up for visual polish of bug 902399

Update to include the new design and guidelines provided by UX regarding the duplicate contact details information screen.

We have kindly asked @rnowm to update the confirm with content BB (http://buildingfirefoxos.com/building-blocks/confirm.html) to properly manage the absence of <img> and/or <small> elements in this BB. In case no <small> element is included, the <strong> element should vertically align with the image or the space reserved for it.