Infinite loop when adding group as member of groups

[gedtn]

There are a few issues with the adding of members to groups:

• Add group member dialog lists current group as option. Selecting the current group will send the action into an infinite loop next time you try to amend the members. This requires deletion of row from db to correct.
• Should existing members be listed in select for add members?
• It was thought that the fixing the first point will not prevent the creation of loops. There is the broader issue of either preventing the creation of loops, or dealing with loops. Have tested further and found that the adding of groups to groups that would create loops does not work - that is, it seems to be already preventing the creation of loops.