packages/orm/obsrvers/creating/html の訳の調整＆未翻訳部分の翻訳
Merge pull request #494 from sharkpp/fix_orm_observers

packages/orm/obsrvers/creating/html の訳の調整＆未翻訳部分の翻訳
documented new download() parameter
added File::exists(), a file exist check that honours the defined area.
Merge branch '1.8/develop' of https://github.com/fuel/docs into 1.8/develop_japanese