WCAG compliance

These updates have been made to Rhythm Portal for WCAG compliance:

• In the Log In widget, the input fields now have area-describedby attributes. Screen readers now properly describe the fields.
• In the Log In widget, the user name field label is now connected to a form control.
• In the Log In widget, screen readers now describe the error when incorrect credentials are specified.
• ARIA landmarks have been added to the Footer content widget.
• The visibility of the focus ring on check boxes is improved.
• Element IDs in Rhythm Portal widgets are now unique.