show reminders for deleted tickets

so user can resolve them from web ui
abort reminders creation in advance if the ticket can't be loaded or is deleted
return the error message if the reminder is not created
test reminders on deleted tickets
Reminders->Add does *not* return txnid
test /Tools/MyReminders for deleted tickets
show process results for /Ticket/Reminders.html
Don't show the New reminder box on deleted tickets
Don't show the "Save" button if there are no reminders and new ones can't be created
Fix tests for no longer giving a useless "New reminder" box on deleted tickets
Merge branch '4.0/reminders-of-deleted-tickets' into 4.0-trunk