Add Japanese translation to webify.php

## Before

[PHPUnit Manual – 第2章 PHPUnit の目標](http://phpunit.de/manual/3.7/ja/goals.html)

![Before screenshot](http://gyazo.com/b51ea98b32245f97ed4c90275eba6a24.png)

## After
![After screenshot](http://gyazo.com/077e1f2558c9c6394dad626b9ccf0ebc.png)

## Translation

**戻る** means "go back"
**次へ** means "to next"

**このページの改善案** means "improvement plan of this page"
**GitHubで提案** means "suggest in GitHub"
**ください** means "please"

"Thanks" I omitted it because it was unnatural in Japanese.