Added knockout library and removed js code to start from scratch
Added code to display number of questions
Added current question index
Updated questions data

It seems there's no need to escape characters now.
Updated to display current questions and its choices
Updated to display selected choice
Added code to ignore form submission
Fixed model not updated when choice is selected
Added code to move to the next question when answer is correct
Updated to select choice by clicking on an item
Added code to display score stars
Added code to highlight star if answer is correct
Added code to increment score when answer is correct
Removed id that is no longer used
Added code enable syntax highlighting

Since the element has to be recreated each time for the highlighting
function to work, the updated isn't handled by knockout directly, but in
a callback that takes care of removing the old node and appending the
new one.
Fixed json data

< and > need to be escaped again, after enabling syntax highlighting
Refactored question code display

The question shoudldn't know anything about the quiz. Hence, the quiz
should pass the question in which element the code should be displayed.
Added code to display error on wrong answer
Updated observable name from errorFound to wrongAnswerSubmitted
Added code to display summary

Stars are not yet displayed in the summary. That will be addressed in a
different commit.