Add README.txt for d6 version

The README.txt for emailpanels is missing there is not much to do, but if you miss some things you will get simply an page not found error and nothing more. It should contain:

1.) Enable "contactemail" in Site building > Pages (admin/build/pages) to provide the contact form under the path email/%node/%field_name.
2.) Add at least one variant and add Widget "CCK Email Contact form" to its content
3.) Go to your panel where you want to include the email contact form link and add the node > field_{email}; set the formatter to "Email contact form".
4.) DON'T FORGET: go to Content management > {content type} > Display fields and set "Email contact form" as formatter for teaser and full node. This is very important, because it won't be enough to set only the pages formatter to "Email contact form"

BTW. I forgot number 4, so I was need to debug the modules emailpanels and email. Number 4 might be fixed also in email module, because it's not obvious that the dodes cck field formatter is used and not the one of panels, is it?.