fix language url redirection.

url redirection with language on uri will now work with no problem.
http://localhost/fuelstart/page will redirect to
http://localhost/fuelstart/{lang}/page
No effect in hmvc request, everything works fine.
change javascript variable use.

change from base_url to site_url.
base_url will generate uri with no index.php/{lang}
site_url will generate uri with index.php/{lang}
the index.php will show or not is up to config.