merge nested default options

[maxklenk]

In this sample scripts.ngConstant.name will not be merged because there is no deep merge for nested objects.

//// task [`scripts`] collects scripts, runs several transformations and concatenates everything
scripts: {
  //  src: ['app/components/**/*.js', '!app/components/**/*.spec.js'], // glob that points to all scripts (except tests)
  //  dest: 'dist/js/', // destination of the concat file `scripts.js` (and associated sourcemaps file)
  //  ng2html: { // adds ng2html and saves all html partials right into the AngularJS $templateCache
  //    src: 'app/components/**/*.html', // glob that points to all partials
  //    prefix: 'components/', // prefix of the URL path
  //    name: 'app.templates' // the module name that contains the partials
  //  },
    ngConstant: { // adds ngConstant to dynamically add variables to your AngularJS app
      constants: env.constants, // the object that contains the variables
  //    name: 'app.config' // the module name that contains the variables
    }
  },