Implement new notification API

[Franz]

With version 1.1.3 Trac changed his notification API (see ​Advanced Notification enhancements).

This new API should also be used in MailPlugin.

The ticket is not critical, since MailPlugin also works fine with 1.1.x (tested with 1.1.6)

[Franz]

Patch for partly implemented API

[Franz]

Patch with new notification API, but not working

[Franz]

Patch XMailEMailModule.py_PARTLY.diff​ is partly working (sends mail, but without subject and encoding is wrong), but it is probably not using the recommended way of the new API (see also module API of ​Package notification).

Patch XMailEMailModule.py_API.diff​ uses probably more of the recommended way, but apparently incorrect, since Trac throws Exception too many values to unpack; stacktrace is:

File "build\bdist.win32\egg\xmail\XMailEMailModule.py", line 522, in run
    self.func()
File "build\bdist.win32\egg\xmail\XMailEMailModule.py", line 161, in _sendAllMails
    notifyer.send_mails(username, notify_data)
File "build\bdist.win32\egg\xmail\XMailEMailModule.py", line 415, in send_mails
    datetime.now(utc), author))
File "build\bdist.win32\egg\trac\notification\api.py", line 358, in notify
    self.distribute_event(event, self.subscriptions(event))
File "build\bdist.win32\egg\trac\notification\api.py", line 369, in distribute_event
    for sid, authenticated, address, transport, format in subscriptions:
too many values to unpack

[Franz]

Patch with new notification API, but not working