Overnumerousness sef patch

This PR fixes the issue with SEF 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.

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This may need some more work to enable only
- Search Engine Friendly URLs

and links like: /index.php/about

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Option
- Adds Suffix to URL

for links like /about.html is not working either