Squashed commit of the following:

commit 16b08cb0729e98e203556c9d85068f96ab0c0d4d
Author: Yuu ISHIKAWA <yuu.ishikawa@gmail.com>
Date:   Tue Apr 2 00:28:32 2013 +0900

    merge ymac setting

commit e62106475fa8435ea9a3376d922e54b240234fae
Author: Yuu ISHIKAWA <yuu.ishikawa@gmail.com>
Date:   Tue Apr 2 00:17:34 2013 +0900

    modify .gitconfig