Set viewport to device width for better mobile display

Magical Meta tags!!! For better display on mobile. Currently, when I look at the site in firefox on android, i either get tiny text or, if i zoom in, i have to scroll horizontally:

![screenshot_2014-09-28-11-16-46](https://cloud.githubusercontent.com/assets/193874/4434740/5e797166-4723-11e4-8f46-980421b1798d.png)
![screenshot_2014-09-28-11-16-23](https://cloud.githubusercontent.com/assets/193874/4434739/5c94253a-4723-11e4-8646-4213ac29ea00.png)

TIL that the incantation to get initial page load and/or double tap zooming to look good is to set the meta viewport to the device width. With this change, it now looks like this!!!

![screenshot_2014-09-28-11-16-04](https://cloud.githubusercontent.com/assets/193874/4434747/798a9048-4723-11e4-8fe7-805e78c0603c.png)