Add icons of asahikawa.spending.jp

I've just added four icons created by @masaru99. They are used in [asahikawa.spending.jp](http://asahikawa.spending.jp/).

* asahikawa_logo.svg
* debt-asahikawa.svg
* japanese_money.svg
* restoration.svg


<http://smagch.github.io/spendingjp-icons/>