This is a successor to #440 rebuilt on top of #594 so that we can merge this while we are still at Hemlfile v0.x without worrying any backward-incompatibility. Much appreciation to @yxxhero for the original work!
Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>
Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>