Improve the registration page:
 * Display developer and commercial differences side by side
 * Display forms only when user has selected a tiers
 * Link to the appropriate page ob mastery if the user has a mashery account
Improve second part:
 * remove checkbox
 * change stop colour
 * add a label header on top of commercial form
Merge pull request #7 from guardian/improve-registration-page

Improve the registration page: