Allauth style changes

Changed headings to sentence case. Removed references to "social networks" and made language more friendly. Added class to style lists and text. Made provider_list output an HTML list element.

Changed the spacing which with throw off the diffs. Sorry.
Fix bug 1036127: Add service icon to profile edit
Fix bug 1036126: Add service icon to header
Merge pull request #2559 from stephaniehobson/allauth

Style changes to Email Addresses and Account Connections pages.
Merge pull request #2555 from openjck/allauth-service-icons

Add service icons to header and profile edit page
Improved the admin dashboard for user centric apps.
Fix newsletter form toggle JavaScript.

This is needed to decouple the JS from the names used for the form fields. In the case of the signup form we're using no form prefix and in caes of the profile edit form we're using a form prefix.
Make email adresses unique.
Make giving an email address in the social signup account form required.
Remove left margin from GitHub login buttons