align package.json description with readme

This irons out a kink in the way harp looks on the new npm website: https://preview.npmjs.com/package/harp

![screen shot 2014-11-05 at 2 25 52 pm](https://cloud.githubusercontent.com/assets/2289/4927355/cec2e7d8-653a-11e4-878a-d1c9b8be4f0c.png)

I'm working on making npm/newww [smart enough to fix these redundancies](https://github.com/npm/newww/blob/b94555fa4d55879ab4c370fa14b7e78924ba82fc/facets/registry/presenters/package.js#L349-L361), but it's still a work in progress.