Can we make this a bit friendlier / more helpful?

```
yepnope.js (aka Modernizr.load) is no longer included as part of Modernizr. Get it from http://yepnopejs.com.
See http://github.com/Modernizr/Modernizr/issues/1182 for more information.
```

Also, I thought the plan was to only error if yepnope isn’t present? (and warn if it is – see below)