Update dependencies and devDependencies

[shinnn]

• grunt.util.async is deprecated, so I replaced it with async module.
• I fixed JSHint setting. Now there is no need to set the "ES5" option explicitly. (cf. http://www.jshint.com/blog/2013-05-07/2-0-0/).
• I moved Blanket configuration in package.json from the scripts field to the config field. (cf. Storing configuration in the scripts field is no longer supported by npm blanket#349)

[watcherdm]

+1

[avdg]

Any comments? Should be fine to merge I guess

[avdg]

(Hmm.. a new npm release would be great too)

[manikandants]

👍
updating blanket to 1.1.7 would fix the following warning too

npm WARN deprecated object-keys@0.2.0: Please update to the latest object-keys

[alex-seville]

And published to npm.