Styling/CSS tweaks.

* A grey border was added around each step content.
* Vertical spacing was adjusted.
* Radio button layout and spacing were adjusted.
* Horizontal borders were added above and below ooyala videos.
Merge pull request #4 from open-craft/css-tweaks

Styling/CSS tweaks.
Hide start over on first step
Fix wikipedia link in readme
Merge pull request #6 from aboudreault/hide-start-over-button

Hide start over on first step
Add various improvements and replaced the default example
Merge pull request #7 from aboudreault/various-fixes

Add various improvements and replaced the default example
Merge pull request #5 from open-craft/dragonfi-create-unittests

Create integration tests
Fixing question numbering by making StepBlock a proper parent
Factor out SeleniumBaseTest into xblock-utils