Re-skin Etherpad

We'd like to re-skin Etherpad to make it fit better into the overall UX and make it simpler to use. The designs can be found at `Dropbox/OAE/22. EtherPad Upgrades/EtherPad.v03.pdf`.

A couple of notes:

- [x] The default font of the Editor should become `Open Sans Regular`, with a default font size of 14px and a default line-height of 18px
- [x] When using `400px` width, no controls should be shown
- [x] The `Document Saved` notification should not be implemented
- [x] The editor should not have a dynamic height. Scrolling inside of the editor is acceptable. However, we should have some media queries to make the height of the editor dependent on the height of the browser
- [x] The print button should just trigger the `Export to PDF` functionality and download the PDF straight away
- [x] Authorship colors should not be shown by default but should be toggle-able from the online dropdown.
I think it would be better to structure like this:

```
#etherpad-container #etherpad-edit-mode {
    height: 700px;
}

@media (max-width: 767px) {
    #etherpad-container #etherpad-edit-mode {
        height: 550px;
    }
}

@media (max-width: 400px) {
    #etherpad-container #etherpad-edit-mode {
        height: 350px;
    }
}
```