Add first two exercises of Chapter 8.
Add solution for exercise 3 of chapter 8.
Add solution for exercise 4 of chapter 8.
Add exercises 6, 7 and 8 of chapter 8.
Add solution for Exercise 8a.
Consume newline characters in the `comment` parser.
Add exercises of Chapter 9.
Add answer of exercise 5.
Add first exercises from Chapter 10.
Add remaining exercises from Chapter 10.
Add first exercises from Chapter 11.
Add remaining exercises from Chapter 11.
Merge branch 'ch08'
Merge branch 'ch09'
Merge branch 'ch10'
Merge branch 'ch11'