GCAAuth: getUserStore: make more scalaesce
[views] login: provide proper 'active'-String to template
[views] register: provide proper 'active'-String to template

Also rename Sign Up to Register
[views] registerDetails: provide proper 'active'-Str. to template
[views] imprint, contact: Don't require a conference

imprint and contact views are conference independent.
[views] If there is no Conference obj, use active as Nav elment

Also if the active element is Register or Login, don't show the
login menu.
[views] conference: Rename Sign Up to Register (be consistent)
[views] dashboard/user: rename active-String to "Abstracts"
Merge pull request #109 from gicmo/cleanUpNav

Clean up navigation links

OK