Start japanese (ja) translation
Translate index.html; fix _config.yml
Translate installation/index.md
Translate installation/mac.md
Translate installation/windows.md
Translate installation/linux.md
Translate installation/deploy.md
Translate installation/upgrading.md
Translate installation/troubleshooting.md
Fix installation/troubleshooting.md - long lines
Update YAML front matter for other pages
Merge pull request #1634 from chibicode/gh-pages

[Translations: /ja] Japanese translation