Integration with omniauth

- Integration with omniauth.
Remove commented code

- Remove commented code
Redirect to client after registration

- Redirect to client after registration.
Redirect to home after signing out

- Redirect to home after signing out at client.
Merge branch sso_omniauth_03_13_2013_a

- Merge branch sso_omniauth_03_13_2013_a into
  sso_omniauth_04_10_2013_a

- Conflicts:
    app/controllers/portal/teachers_controller.rb
    app/models/user.rb
Fix error on registration

- Fix error on registration.
Set domain to cookies for sso integration

- Set domain to cookies for sso integration.
Delete cookies with domain

- Delete cookies with domain for sso integration.
reidrect to root on sign out

- reidrect to root on sign out.
Merge remote-tracking branch 'zeus/sso_omniauth_04_10_2013_a' into wip-oauth-runtime-connection

enable a OAuth2 provider in the portal
update schema.rb and Gemfile.lock