Update imap_and_smtp.rst

Insert the trigger in the proper database.
Merge pull request #521 from tonioo/1.1.x

Update imap_and_smtp.rst
Documentation update.

fix #519
Merge branch '1.1.x' of github.com:tonioo/modoboa into 1.1.x
Merge pull request #524 from tonioo/1.1.x

1.1.x
Documentation update.

Version 1.1.1.
Merge branch 'master' of github.com:tonioo/modoboa
Record current user instead of an old one.

fix #526
Merge branch '1.1.x'
Adding missing file.
Merge branch '1.1.x'
Quick support for non existent mailbox with children.

fix #525
Merge branch '1.1.x'
Upgrade instructions.

see #526
Merge branch '1.1.x'
Manage revisions manually.

fixes #527
Merge branch '1.1.x'
Update plugin_api.rst

Import for ModoExtension was needs to be from modoboa.core.extensions.
Merge pull request #529 from jag3773/patch-1

Update plugin_api.rst
Documentation fixes.