Description of Problem:

Cyrus IMAP and other IMAP sever implementations use the IMAP ALERT
response to display warnings to the user, for example when their mailbox
quota is nearly used up.

Evolution ignores the ALERT status response, and thus ignores RFC 2060
which specifically states:

| The currently defined response codes are:
|
|      ALERT          The human-readable text contains a special alert
|                     that MUST be presented to the user in a fashion
|                     that calls the user's attention to the message.

I've tested this in Mozilla Thunderbird, and the ALERT is properly
acknowledged - on an account with a low quota the user is warned that
their quota is at x%


Steps to reproduce the problem:

Debugging the server/client communication shows:

received: * FLAGS (\Answered \Flagged \Draft \Deleted \Seen $MDNSent Junk)
received: * OK [PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted 
\Seen $MDNSent Junk \*)]
received: * 70 EXISTS
received: * 0 RECENT
received: * OK [UIDVALIDITY 1071782264]
received: * OK [UIDNEXT 23707]
>received: * NO [ALERT] Mailbox is at 92% of quota
received: A00119 OK [READ-WRITE] Completed
sending : A00120 UID FETCH 1:23706 (FLAGS)


Actual Results:

Evolution breaks RFC 2060 and does not display any warning to the end-user.


Expected Results:

Evolution should display some form of alert to the end-user.