Squashed commit of the following:

commit e853ebb9097f7b7bd12e64731b0d3256e75eb07d
Author: cubicdaiya <cubicdaiya@gmail.com>
Date:   Fri May 30 20:40:48 2014 +0900

    remove -verbose

commit 34cdedcdf00599b5e124a38939f6f3aae5a055af
Author: cubicdaiya <cubicdaiya@gmail.com>
Date:   Fri May 30 20:37:07 2014 +0900

    use 'checkout' instead of 'co'

    co is not git-command

commit 3f09ca04279e378dc612aa068e5de1126f98a3c7
Author: cubicdaiya <cubicdaiya@gmail.com>
Date:   Fri May 30 20:32:16 2014 +0900

    fix travis-ci's build