Fix for #7 - problem with initializing CAS

This fixes #7 which causes:
phpCAS error: phpCAS::isAuthenticated(): one of the methods phpCAS::setCasServerCACert() or phpCAS::setNoCasServerValidation() must be called. in ........../vendor/xavrsl/cas/src/Xavrsl/Cas/Sso.php on line 199

In short, you need to configure SSL validation before attempting to detect_authentication.