Updated update.php For New Logged In Feature

Adds columns require_log_in and require_log_in_text to quizzes table to allow user to require a user is logged in when taking quiz.
Updated quiz_options.php - Edit Logged In Feature

This allows the user to edit the option to require a user to be logged in and edit the text that is shown when a user is not logged in.
Updated quiz.php To Require Log In

Added ability to require user is logged in. If user is not logged in when required, then the require_log_in_text is shown with a log-in form.
Update quiz_options.php-Fixed Duplicate Radio Bug

Accidentally named the radio buttons for both require log in and user email the same id. Fixed in this update.
Update quiz_options.php-Added Variables To Text

Added the variables %QUIZ_NAME% and %CURRENT_DATE% to the text for users not logged in.
Merge pull request #29 from fpcorso/feature/3

Added Feature To Require Log In Resolves #3