Implement "ch02/Common Haskell Types" examples
Implement "ch02/type_variables" examples
Implement "ch02/type_classes_101" examples
Implement 'ch03/pattern_matching' examples (in progress)
Implement 'ch03/pattern_matching' examples
Implement "ch03/guards_guards" examples (in progress)
Implement "ch03/guards_guards" examples
Implement 'ch03/where' examples (in progress)