added function for clearing cookies

www/cookie-handler.js

@@ -1,12 +1,17 @@
 var pluginId = module.id.slice(0, module.id.indexOf('.'));
 var ToughCookie = require(pluginId + '.tough-cookie');
 var WebStorageCookieStore = require(pluginId + '.local-storage-store');
-var store = new WebStorageCookieStore();
+
+var storage = window.localStorage;
+var storeKey = '__advancedHttpCookieStore__';
+
+var store = new WebStorageCookieStore(storage, storeKey);
 var cookieJar = new ToughCookie.CookieJar(store);
 
 module.exports = {
     setCookie: setCookie,
-    getCookie: getCookie
+    getCookie: getCookie,
+    clearCookies: clearCookies
 }
 
 function setCookie(url, cookieStr) {
@@ -17,3 +22,7 @@ function setCookie(url, cookieStr) {
 function getCookie(url) {
     return cookieJar.getCookieStringSync(url);
 }
+
+function clearCookies() {
+    window.localStorage.removeItem(storeKey);
+}