Keep in same page when switching languag

for osCommerce Online Merchant v2.3

When Multi Language Support is activated in Ultimate Seo Urls 5, the links will not keep the user on the same page when the user switches language (on clicking a language flag, wherever the user is in the site they will be taken to the index page). This contribution modifies this behavior, so the user is kept in the same page. This package includes only the files that should be modified from the standard Ultimate Seo Urls 5 PRO for osCommerce 2.3.1