New Italian translation of chapter 3, need revision now
New Italian translation of chapter 4, need revision now
Finished translation of chapter 3 to German

Finished translation of chapter 3 to German after - finally - two
revisions.
Italian chapter 3 review by Claudio Chisari.
Italian chapter 4 review by Claudio Chisari.
Fix ebook creation for Italian and Dutch languages.
Staging -> l'index
[ko] revert font setting in latex/config.yml

Revert before ee73af4544669856a32c9b26dd9e598f74c52b01.
It was a mistake.
Poprawa powtarzającego się słowa.
[ko] chapter 1~6: Update by 9518677
把部分地方的语句理顺了一点，更精确，更容易理解(smoothen some chinese sentences, to be more accurate and easier to understand)
update part 3 of chapter2 of the chinese translation, make it more accurate and easier to understand
update chinese chapter2 and chapter3, more accurate and easier to understand, use more common computer chinese terminologies for chinese reader to follow
Fix a typo in the quote.
[ko] chapter 6: revert Plumbing tool
[ko] README: Type correction
[ko] chapter 1~6: Change Words

나->필자
참조->레퍼런스
원격->리모트
[ko] add 'thanks' in latex config
[fr] fix figure hyperrefs
[fr] fix chapter 3 discrepancies in figure translations and typos