Add NPM script aliases for the registered Grunt tasks
Add NPM script aliases for the registered Grunt tasks

Not everybody has or should need to have grunt-cli installed globally:
This allows people to use NPM to trigger grunt builds, without needing
to know how they work under the hood.

`npm test` remains the full Grunt suite, for use with Travis.

WP-API/node-wpapi,WP-API/node-wpapi,gerhardsletten/wordpress-rest-api,brad-decker/wordpress-rest-api,brad-decker/wordpress-rest-api,gerhardsletten/wordpress-rest-api,kadamwhite/wordpress-rest-api,kadamwhite/wordpress-rest-api,kadamwhite/wordpress-rest-api