[it] Chapters 1-4: Apply uniform style of translation. Minor corrections. Update the translation.
[ja] Apply bc3f922f2549e44524dc11301d1e53c984b14a1b
Merge pull request #406 from tecnomente/master

[it] Chapters 1-4: Apply uniform style of translation. Minor corrections. Update the translation.
Merge branch 'master' into fix-chapter1
Merge pull request #408 from harupong/fix-chapter1

[ja]Fix chapter1