Improve Distribution Wizard step buttons (order, position)

During the usability sessions with users (7 beginners + 2 medium), the majority of them had problems going through the full wizard the first time.
· 6/9 Later
· 1/9 Never
· 2/9 Install

There are various reasons for this, like:

• complex look of DW which scares a bit the users;
• missing 'Continue' button from .stepButtons: users are accustomed to click 'Next - Next - Next' inside the wizards, without reading the instructions. 'Continue' disappearing from that area, they press on the next-best-thing.

There are some ideas that could improve the interaction:

• Idea1: Separate 'Later' and 'Never' buttons from 'Continue', see idea1_current.png and idea1_proposal.png

• Idea2: Move 'Continue' button in the .stepButtons zone, see idea1_proposal.png

• Idea3: Replace (.button-group .dropdown-toggle) with a radio, see idea3_current.png and idea3_proposal.png