Fix error message generation for site notices.

- Prevent 'Cancel' link from generating duplicate error lightbox.
Remove user model and controller

- Remove user model and controller.
Refine css for  tabs in class materials page.

- Refine css for  tabs in class's materials page.
Add Devise to RITES portal

- Add Devise implementation to RITES portal

- Disable Restful Authentication
Add Welcome text for current_user

- Add Welcome text for current_user.
Fix feature tests to accommodate devise changes

- Fix feature tests to accommodate devise changes.
Remove redundant spec tests.

- Remove user_controller_spec, sessions_controler_spec and
  authenticated_system_spec.
Merge UI fixes

- Merge branch 'ui_fixes_for_cc_02_20_2013_a' into
  add_devise_from_scratch_02_20_2013_a
Fix devise login error messages display

- Fix devise login error messages display

- Modify devise login error message text
Handle user roles with devise login

- Handle user roles with devise login
Modify user registration to work with Devise

- Modify user registration to work with Devise implementation

- Use custom mailer class instead of Devise to send confirmation mails
Add default from address to Usermailer class

- Add default from address to Usermailer class
Handle login and switch user with devise

- Handle login and switch user with devise.
Handle users edit, reset password

- Handle users edit, reset password
Redirect to recent_activity page

- Redirect to recent_activity page for portal teacher
Set mailer default url for use with Devise

- Set mailer default url for use with Devise
Set mailer default url for use with Devise

- Set mailer default url for use with Devise
Set mailer default url for use with Devise

- Set mailer default url for use with Devise
Show error message on login already taken

- Show error message on login already taken
Fix render after authentication failure

- Fix render after authentication failure