from official cordova website
http://cordova.apache.org/news/2013/10/21/cordova-registry.html
From anywhere within an app’s directory, plugins can be added to a project with
cordova plugin add [PLUGIN_ID]
where PLUGIN_ID is the id (typically reverse-domain style) shown on the plugin registry website. You can also download a specific version of a plugin:
cordova plugin add [PLUGIN_ID]@[VERSION]