Fix potential XSS vulnerability on user's name

Names parsed from incoming emails are stored in the database as is. This pull request addresses potential XSS vulnerability due to improper display of unsanitized names.
If we do
```php
htmlentities( (string) $var, $flags, 'UTF-8', false);
```
(add `$double_encode = false` to the argument list), then I think we can go ahead and sanitize the user name when saving to the database