Warning title Tag should have the same as the Alt

As for this page http://wet-boew.github.io/wet-boew/demos/archived/archived-en.html

They are using the same word for the alt tag and the title tag.
```php
<img src="../../dist/js/images/archived/warning.gif" alt="Warning" title="Warning" class="margin-bottom-none">
```

So we can drop this line in the config file

```php
$_SITE['wb_archive_warn_title_'.$_LANG_] = $_SITE['wb_archive_warn_alt'.$_LANG_];
```
Merge pull request #88 from crochefort/patch-1

Warning title Tag should have the same as the Alt