Exercise 17.6.1
Exercise 17.6.3
Exercise 17.6.4
Exercise 17.6.5
Exercise 17.6.6
Exercise 17.8.3
Exercise 17.8.4
Exercise 17.8.5
check if two web pages are the same
Exercise 17.8.7
Exercise 17.8.8
Exercise 17.8.9
bugfix: move stuff from chapter14 to chapter17
Exercise 18.1.1
Exercise 18.1.2
Exercise 18.1.3
Exercise 18.1.4
Exercise 18.1.5
Exercise 18.1.10
Find rock star