Do not install `motd-tail` recipe.

This commit refs #65.
Add tests for slime `motd.tail`.

This commit refs #65.
Download the `slime-all` motd-tail template file.

see: [Linux - motd に Dragon Quest のキャラクターのドット絵を表示させる - Qiita](http://qiita.com/makocchi/items/5549c41526d6a6cabab1)

This commit refs #65.
Fix typo: rename the downloaded file from `motd.taild` to `motd.tail`.

This commit refs #65.
Merge pull request #65 from kazu634/id/65

motd-tailでスライムを表示させる