Copied original file
Translated all titles.
Added some drafts
Transslated ja/core-utility-libraries/app.rst
Reset .gitignore
Reset .gitignore
Corrected line feed characters to LF from CRLF
Corrected some fault according to reviews.
Merge pull request #690 from zuborawka/ja-app

Translate ja/core-utility-libraries/app.rst