Add a short (visit-able) URL to the grunt report

Add a short URL (generated by the client) to the grunt report.

Screenshot below is on an 80 character width terminal:

![screenshot from 2014-04-18 20 39 57](https://cloud.githubusercontent.com/assets/271622/2745125/5ed1d774-c731-11e3-9272-dd6f9719d315.png)

Later should you add a short/visit-able URL to the APi response this update will use the value stored at `result.advisory.short_url`.