fix mailfilter ignoring some incoming mails

mailfiter uses changeRecorder() only as a monitor and so the slots
must not call changeProcessed(). So we need to override all functions
processing the notifications because their default implementations
do call changeProcessed(). But changeProcessed() dequeues a notification
from pendingNotifications if there are any, and if it does, a
notification is lost.

A better fix would be to change the default implementations such
that they only call changeProcessed() if changeRecorder() is
in recorder mode.

FIXED-IN: KDE/4.10.1
BUG: 292497
BUG: 282063
BUG: 276635
BUG: 255388
BUG: 293032
BUG: 299589
BUG: 299968
BUG: 311199
BUG: 313420
DIGEST: if more than one mail is received in one batch, mail filtering ignored some mails