updated header to only show not me on auth page
using rails helper instead of string
resolving dependency on request object
Don't show scope groups for groups not requested

If the filtered scopes (requested scopes) for a particular
scope group is empty, don't show the scope group <li>
and <h2> tags (don't show the group at all, really).
Implement requested changes from #191

Account --> Your Profile
This is not me --> functional sign out link

There's an issue where "This is not me" should allow switching
of accounts.  Will file an issue for that.
Merge pull request #233 from 18F/feature/not-me

Only show This is Not me on the oauth authorize page
Merge pull request #242 from 18F/hotfix/limit-scope-groups-ui

Don't show scope groups for groups not requested
Merge branch 'devel' into feature/api-logout