Give badges height

Stops the page jumping around

Note, assumes the badge image is at least 90px high - if smaller, there'll be white space, if higher, it will jump up

## Before

![badge-before](https://cloud.githubusercontent.com/assets/74132/3705144/b07fdb98-141b-11e4-8d14-8a0ecea9f551.gif)

## After

![badge-after](https://cloud.githubusercontent.com/assets/74132/3705163/d5c608b4-141b-11e4-9dc0-57347a5054eb.gif)