Squashed commit of the following:

commit ff949f9d7e3118634c6c8aed513f0709fe6a05bc
Author: Hayaki Saito <user@zuse.jp>
Date:   Fri May 2 10:32:19 2014 +0900

    Fix a typo

commit d551b421e9cfae2e2dc5eedea83c2d3fae2edbe9
Author: Hayaki Saito <user@zuse.jp>
Date:   Fri May 2 10:23:38 2014 +0900

    Update travis build

commit d98e174afe4cc353ff5aa154f3e0c55b65c8d6e6
Author: Hayaki Saito <user@zuse.jp>
Date:   Fri May 2 10:19:31 2014 +0900

    Update travis build

commit bccc8145faa03b2fd56c777ace7aedd38cd5a0b6
Author: Hayaki Saito <user@zuse.jp>
Date:   Fri May 2 10:06:47 2014 +0900

    Fix travis build

commit 53c98ad4740eeffaf179e314c21a690d3a0524f9
Author: Hayaki Saito <user@zuse.jp>
Date:   Fri May 2 10:00:39 2014 +0900

    Fix travis build

commit aef80bdbbdb36d51073326477894c837672975f6
Author: Hayaki Saito <user@zuse.jp>
Date:   Fri May 2 09:57:59 2014 +0900

    Update .travis.yml