Improve class3 exercises
Add a scratch pad
Fix bugs in class3 exercise3 specs (thanks Amanda)
Re-word instructions for class2 exercise 3
Remove class4 git_config
Fix exercise name
Tweak branching example
Improve class4 exercises
Tweak TIP
Remove class5 git_config
Remove class5 songs
Remove class5 target images
Remove class5 gitignore file
Improve class5 exercises
Fix typos
Fix typo
Add class5 exercise5
Improve branching and looping guides
Fix bug
Improve readability