Build: Use jQuery 4.0.0 for demos; update RequireJS from 2.1.14 to 2.3.8

Closes gh-2383

Author: mgol

Gruntfile.js

@@ -253,8 +253,8 @@ grunt.initConfig( {
 				"jquery-simulate/jquery.simulate.js": "jquery-simulate/jquery.simulate.js",
 				"jquery-simulate/LICENSE.txt": "jquery-simulate/LICENSE.txt",
 
-				"jquery/jquery.js": "jquery-3.x/dist/jquery.js",
-				"jquery/LICENSE.txt": "jquery-3.x/LICENSE.txt",
+				"jquery/jquery.js": "jquery/dist/jquery.js",
+				"jquery/LICENSE.txt": "jquery/LICENSE.txt",
 
 				"jquery-1.12.4/jquery.js": "jquery-1.12.4/dist/jquery.js",
 				"jquery-1.12.4/LICENSE.txt": "jquery-1.12.4/LICENSE.txt",

bower.json

@@ -16,9 +16,9 @@
 		"jquery-mousewheel": "3.2.2",
 		"jquery-simulate": "1.1.1",
 		"qunit": "2.19.4",
-		"requirejs": "2.1.14",
+		"requirejs": "2.3.8",
+		"jquery": "jquery#4.0.0",
 		"jquery-1.12.4": "jquery#1.12.4",
-		"jquery-3.x": "jquery#3.7.1",
 		"jquery-2.2.4": "jquery#2.2.4",
 		"jquery-3.0.0": "jquery#3.0.0",
 		"jquery-3.1.0": "jquery#3.1.0",