Upload

- Adding helper classes `icon-lg` `icon-sm` & `hr-first`
- Fix directive evFixedHead (problem of margin in empty header div)
- You can now cancel current upload in evUpload
![giphy](https://cloud.githubusercontent.com/assets/1775934/4118863/03f0adcc-32a6-11e4-9b93-a5c35386027a.gif)

T'as :two:  events on('error') et :two: events on('complete').