demo.html example update

Added example of localStorageService.remove('key'); and localStorageService.removeAll();

demo/demo.html

@@ -69,6 +69,10 @@ var YourCtrl = function($scope, localStorageService, ...) {
   localStorageService.set('localStorageKey','Add this!');
   // Read that value back
   var value = localStorageService.get('localStorageKey');
+  // To remove a local storage
+  localStorageService.remove('localStorageKey');
+  // Removes all local storage
+  localStorageService.clearAll();
   // You can also play with cookies the same way
   localStorageService.cookie.add('localStorageKey','I am a cookie value now');
 }</pre>