Change to Google Group

[edinbur...@gmail.com]

I've changed the way the google group is managed - - - the group has now become "invite only" so the process to join the list is to e-mail edinbur...@gmail.com and then we'll send an invite out. 

This avoids a membership request sitting in a pending state and not being noticed (which has happened in a number of cases since Google changed the Groups interface).

I've updated the website to indicate this as well.

Best Regards,

rob.