Enabled Sign-In Feature and Improved for Root Timeline Creation

- Enabled Sign-In Feature: Signing-in redirects the user back, changing the profile does not redirect to personal collection. Therefore, authoring is still not exposed but we can start registering users to engage them with updated.

- Improved scenario for root timeline creation: Instead of creating a "Cosmos" timeline, users get the create timeline dialog and are able to set their timeline parameters there.

Code Review (Approved): http://mrccodereview.cloudapp.net/ui#review:id=1212
Deployment: http://cz-july2013-javierluraschi-fixes.azurewebsites.net/