Refactored for easy quiz additions

You only need to add the quiz to index.html and add your file to js/questions/[question name].js
For example you will still need to add a line to index.html
<option value="pythonProgramOutput">Python Program Output</option>

When quiz.html receives questionType=pythonProgramOutput it will load js/questions/pythonProgramOutput.js.

It will then set questionFunc = pythonProgramOutputQuestion and quizname = pythonProgramOutputName

This will make it easier to add new question types without modifying 3 files.