Colorize created path as cyan (using chalk)

- Add [chalk](https://github.com/sindresorhus/chalk) as dependency.
- Output the name of the files that have been created colorized in cyan and without quotes, which is arguably more readable.

The format will become unified with `grunt-contrib-less` and `grunt-contrib-coffee` (see https://github.com/gruntjs/grunt-contrib-coffee/pull/79), and hopefully with `grunt-contrib-sass` (https://github.com/gruntjs/grunt-contrib-sass/pull/81).