- Made folder/Maildir.py/deletemessage() more tolerant if a message
asked to be deleted already has been.
- In Base.py/copymessageto(), no longer bother calling getmessage()
unless a folder's storemessages() returns true. This will also help
with syncing to LocalStatus if the user deleted messages in the
Maildir since the cachemessagelist() was called.
