Beginning visual styles.
Added basic responsiveness.
Added vendor prefixes for maximum compatibility.
Changed breakpoint to 500px to cover landscape orientation.
Added Firefox logo.
Styled placeholder text.
Updated intro screen to better match mocks.
Merge branch 'develop' into issue-197-gettin-visual-visual
Reformatted linear gradient definitions.
Merge pull request #211 from mozilla/issue-197-gettin-visual-visual

Visual Styles

r+. Nice to do business with you.
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.
* Mocha tests now run as part of the intern functional tests.