[de] Fix headings, remove extra chapters.

Fixes issue #360.
Fix confusion between changes and revisions.
Merge pull request #362 from GArik/EN

Fix confusion between changes and revisions.
Merge pull request #361 from GArik/DE

[de] Fix headings, remove extra chapters.
[ja] Fix typo
Merge pull request #363 from yuta-aoyagi/ja-fix-typo

[ja] Fix typo