[WIP] #33 制御構造を用いたフォーム画面のファイル分割

### !WIP!

- [x] 分割計画を詰める(以下140616修正後)
- [x] 共通部品
  - [x] db_connect.php
- [x] index.php
  - [x] index.php
  - [x] index.html.php
- [x] form.php
  - [x] form.php
  - [x] pref.php
  - [x] form.html.php
- [x] confirm.php
  - [x] confirm.php
  - [x] confirm.html.php
- [x] done.php
  - [x] done.php
  - [x] done.html.php

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レビュー対応
- [ ] xxx