Move introduction above call to action, minor style changes
Add CSS3 social sign in buttons
Remove repo URL from the maintainer signup

Due to the issue with repo's not necessarily being on github or
having correct ownership
Clarify maintainer sign up form.

If we use oauth then the people dont need to use the same email
as their github right?
Merge pull request #1 from daleharvey/front-page-work

Some small work to the front page