Uses outdated Grunt tasks

[vladikoff]

This configuration:

    // default lint configuration, change this to match your setup:
    // https://github.com/cowboy/grunt/blob/master/docs/task_lint.md#lint-built-in-task
    lint: {
      files: [
        'Gruntfile.js',
        'app/static/js/**/*.js',
        'spec/**/*.js'
      ]
    },

    // specifying JSHint options and globals
    // https://github.com/cowboy/grunt/blob/master/docs/task_lint.md#specifying-jshint-options-and-globals
    jshint: {
      options: {
        curly: true,
        eqeqeq: true,
        immed: true,
        latedef: true,
        newcap: true,
        noarg: true,
        sub: true,
        undef: true,
        boss: true,
        eqnull: true,
        browser: true
      },
      globals: {
        jQuery: true
      }
    },

is as of Grunt 0.3 and doesn't work anymore