Add custom html.tpl.php

I discovered in research, for the iPhone to work
properly, it wants to see:

<meta name="viewport" content="width=device-width, initial-scale=1.0" />
So I put it in.

https://drupal.org/node/1468582
http://stackoverflow.com/questions/13002731/responsive-design-media-query-not-working-on-iphone