Add support for COPPA

fixes #83
Merge pull request #167 from mozilla/issue-83-coppa

Add support for COPPA
Web Fonts FTW!

* Use Clear Sans for body text, Fira Sans for headings.
* Add the font middleware and font sets

Additional work to be done:
* The font set needs updated to serve more minimized locale specific fonts.
* The grunt build step needs to be updated to include fonts.css for each locale to minimize the number of requests.

fixes #196
Merge pull request #198 from mozilla/issue-196-fonts

Web Fonts FTW!
Add the fx-desktop channel & start to set up front end unit tests.

* add mocha & chai to the bower config.
* Add a functional test shell for the confirm screen.
Go to the correct page on startup if the browser supports Fx events.