Transalte chapter 38

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Translate chapter 39

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Translate chapter 40

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Translate chapter 41

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Translate chapter 42

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Merge pull request #45 from sjp38/master

Translation for chapter 38 ~ 42