Improved Gruntfile.js for istanbul
Fixed rename a method, install -> use

commit ca655bab75706900c3f9cf8f20e72d08a20486e6
Author: mohayonao <mohayonao@gmail.com>
Date:   Wed Oct 30 15:49:46 2013 +0900

    build

commit 996ffcb7594cb605dc82a806059ebcade8ea1350
Author: mohayonao <mohayonao@gmail.com>
Date:   Wed Oct 30 15:49:29 2013 +0900

    Fixed rename a method, install -> use
Fixed callback error