CKBuilder - Development CKEditor 4 : Plugin/lang files not getting omitted?

I've built a development version of ckeditor 4 on Windows 7 (using cygwin to run the shell script) and on Linux, but it seems to be including all plugins and language files rather than just the ones specified in the build-config.js. Is this a known issue? I'm using CKBuilder 1.6 (auto-downloaded) and Java 1.7 (Windows), Java 1.6 (Linux).

Contents of the build-config.js:

var CKBUILDER_CONFIG = {
    skin: 'moono',
    ignore: [
        'dev',
        'README.md',
        '.gitignore',
        '.gitattributes',
        '.mailmap',
        '.idea'
    ],
    plugins: {
        about: 1,
        basicstyles: 1,
        button: 1,
        clipboard: 1,
        dialog: 1,
        dialogui: 1,
        enterkey: 1,
        entities: 1,
        fakeobjects: 1,
        floatingspace: 1,
        indent: 1,
        link: 1,
        list: 1,
        pastetext: 1,
        toolbar: 1,
        undo: 1,
        wysiwygarea: 1
    },
    languages : {
        'en' : 1,
        'en-au' : 1,
        'en-ca' : 1,
        'en-gb' : 1
    }
};

Screen shot of the output attached - there is one small warning but other than that it doesn't seem to be generating any obvious errors.

Thanks for any help you can give,

Helen