update year in copyright message
include NOTIFY into the list of triggering IMAP commands
fetchmail_wakeup: stop looping when command was found

In the Dovecot 2.1+ case. stop searching for the correct command, after
the correct one has been found and fetchmail_wakeup() has been called.
fetchmail_wakeup: make sure client->user is defined

Before trying to get values based on client->user, make sure it is defined.
fetchmail_wakeup: make all handler_t functions static
fetchmail_wakeup: fix bug in i_debug() arguments

In addition to it, update some message texts, and add one message.
clarify that dovecot 2.2 is supported too

Now that I have had the chance to test it with the latest fixes,
I am confident it works with dovecot 2.2 too.
ChangeLog: release version 2.1.1