Doesn't correctly handle servers with different separators

[rwarford]

The code has a bug which causes it to use the same mailbox separator on both servers. Some servers use different separators. For example, one server might use '.' so the path would be 'INBOX.Spam' while another might use '/' making the path 'INBOX/Spam'.

The solution is to capture the separator individually for each server. I will create a pull request with a fix.