Build: add accessibility testing

Fixes jquery-archive#99

Gruntfile.js

@@ -1,11 +1,10 @@
 module.exports = function( grunt ) {
-	grunt.loadNpmTasks("axe-grunt-webdriver");
-	var path = require( "path" );
-	require( "load-grunt-config" )( grunt, {
-		configPath: [
-			path.join( process.cwd(), "tasks/options" ),
-			path.join( process.cwd(), "tasks" )
-		],
-		init: true
-	} );
+var path = require( "path" );
+require( "load-grunt-config" )( grunt, {
+	configPath: [
+		path.join( process.cwd(), "tasks/options" ),
+		path.join( process.cwd(), "tasks" )
+	],
+	init: true
+} );
 };

tasks/options/axe-webdriver.js

@@ -1,4 +1,6 @@
-module.exports = {
+module.exports = function( grunt ) {
+grunt.loadNpmTasks("axe-grunt-webdriver");
+return {
 	firefox: {
 		options: {
 			threshold: 0
@@ -7,3 +9,4 @@ module.exports = {
 		dest: 'tmp/gu.json'
 	}
 };
+};