Correct tel: link in listings

[danmunz]

The data from HUD JSON serves phone number as "###-###-####" and occasionally as "###-###-####-###," which I assume is a weird way of attaching the extension. It looks like we need to:

• Grab that from the JSON
• If there are three hyphens in the string, convert the last one to an comma (this seems to work: http://stackoverflow.com/questions/9838775/problems-using-extensions-in-tel-hyperlinks-on-android-4)
• Append +1 to it in the link