Deleting the plugin no longer erases your data

Fixed

• Removing the plugin dropped your campaigns, contacts, lists and settings. Uninstalling is now non-destructive. To erase everything on purpose, use Settings, then Danger Zone.
• Two overlapping send workers could pick up the same recipients and send a broadcast twice. Recipients are now claimed before sending, which matters most on large lists.
• Open tracking was dropped on emails whose HTML had no closing body tag.