Overnumerousness seo patch

This PR fixes the issue with SEO url's on the main site.

It adds an hidden field to the com_config.application.xml form which lets configuration save '/' as the $live_site.

Now, when these two options are on:
- Search Engine Friendly URLs
- Use URL rewriting

SEF links will be working fine. This may need some more work to enable only
- Search Engine Friendly URLs
and links like: /index.php/about

Option
- Adds Suffix to URL
for links like /about.html
are not working either