Implement RFC 2595 LOGINDISABLED

[Sebastian Spaeth]

Pushed to 'next' branch:

commit 1ac9dc7fb42f797e94f5c8c30b767b1e111fc945
Implement RFC 2595 LOGINDISABLED

Warn the user and abort when we attempt a plaintext login, but the
server has explicitly disabled plaintext logins.

Sebastian
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: not available
URL: <http://alioth-lists.debian.net/pipermail/offlineimap-project/attachments/20110919/397c6bcb/attachment.sig>