Update README.md

Initial listing of add-ons specific to this fork.
Update README.md

Add the initial Addon Listing
Create seo_header_sql.txt

Install SQL alterations for SEO Header Reloaded
Update advanced_search_result.php
Create .gitignore

Files to ignore for upload to public repository
Complete SEO Header Tags Reloaded

Installation of SEO Header Tags RELOADED
http://addons.oscommerce.com/info/8864

Updated README.md for the new addon
Merge pull request #1 from newburns/SEO-Header-Tags-RELOADED-addon

Seo header tags reloaded addon