Bump grunt-contrib-uglify from 1.0.1 to 2.0.0

Sets `screwIE8` to false as it is now enabled by default

Files Changed:
build/wp-admin/js/customize-nav-menus.min.js
build/wp-admin/js/customize-widgets.min.js
build/wp-includes/js/customize-loader.min.js

Changelog:
2016-07-19   v2.0.0   Update uglify-js to v2.7.0. screwIE8 is enabled by default.
2016-07-19   v1.0.2   Update grunt to ^1.0.0. Fix beautify when passed as an object. Fix docs about report values.

See #38199.



git-svn-id: https://develop.svn.wordpress.org/trunk@39117 602fd350-edb4-49c9-b593-d223f7449a82

Gruntfile.js

@@ -443,7 +443,8 @@ module.exports = function(grunt) {
 		},
 		uglify: {
 			options: {
-				ASCIIOnly: true
+				ASCIIOnly: true,
+				screwIE8: false
 			},
 			core: {
 				expand: true,

package.json

@@ -20,7 +20,7 @@
     "grunt-contrib-imagemin": "~1.0.0",
     "grunt-contrib-jshint": "~1.0.0",
     "grunt-contrib-qunit": "^1.2.0",
-    "grunt-contrib-uglify": "~1.0.1",
+    "grunt-contrib-uglify": "~2.0.0",
     "grunt-contrib-watch": "~1.0.0",
     "grunt-includes": "~0.5.1",
     "grunt-jsvalidate": "~0.2.2",