Finish Create Quiz

In Database, "question.txt" stores each question  in a quiz we
generated; "question_type.q_type" stores the type of a question and
"question_type.parameters" stores the hint alone with this question;
"quiz_question_choice.txt" stores the choice and
"quiz_question_choice.iscorrect" tells if this choice is correct or not.
Small Modification on View_quiz and Edit_quiz