installation/upgrade.html を修正
general/extending_core.htmlを一部翻訳
validation/validation.html を一部翻訳
Merge pull request #278 from raben/1.6/develop_japanese

1.6/develop japanese
Merge pull request #279 from kenjis/fix_upgrade

installation/upgrade.html を修正
Merge pull request #280 from sharkpp/1.6/develop_japanese

general/extending_core.htmlを一部翻訳
Merge pull request #281 from tatsuyaueda/patch-3

validation/validation.html を一部翻訳
packages/orm/observers/included.html 一部修正
Merge pull request #282 from seckie/fix_orm

packages/orm/observers/included.html 一部翻訳