Fix typo
Merge pull request #487 from makimoto/fix-typo-in-2013-12-21-en

Fix typo in 2013-12-21 [en]
Translate 2013-12-21-semantic-versioning-after-2-1-0 into ja
Merge pull request #488 from makimoto/translation-2013-12-21-into-ja

Translate 2013-12-21-semantic-versioning-after-2-1-0 into ja
Remove link to installation guide in documantation [ja]
Rename link-refs in /ja/documentation