(imported from commit 04be792bb480d5e5db1c91d296d1000cf1682571)
(imported from commit 5bd0aa3c49d6ff95559a73bd5f134cc50ae98ce9)
(imported from commit 1132553b63ae23ebcca746f0f65205b97bfee7dc)
The queued email gets deleted if the user signs up before it gets sent. Otherwise, they are reminded in 2 days that they still haven't signed up. This addressses Trac #1812 (imported from commit c1bdc09c03ac576b08986e56994de72d52fd293b)