Bump deps

* I updated [concat-map](https://github.com/substack/node-concat-map) and [tape](https://github.com/substack/tape).
  * Currently I'd like to use brace-expansion on browser. [concat-map v0.0.1 supports IE6-8](https://github.com/substack/node-concat-map/commit/27b9a4a19eb2c3501bc40b633d54a8e99c08765b).
* I changed image format of the badge from PNG to SVG. SVG badges look beautiful on retina displays.