simplesamlphp_auth 7.x-2.0-alpha2

Changes since alpha1:

• Issue #1912426: Provide public API functions by colan: Started adding public functions.
• Issue #1443700: Broken logging for missing e-mail addresses & usernames by colan: Fixed bad log reporting for missing SAML username.
• Issue #1912262: Empty string in username attribute causes DB integrity constraint violation by colan: Ensure empty string isn't assigned to drupal username.
• Issue #1443700: Broken logging for missing e-mail addresses & usernames by colan: Provide better end-user warning & fix bad use of t().
• Issue #1744676: Local Drupal Account Default Behavior Instructions on Admin by colan: Explain that all can log in locally if list is empty.