This fixes the 'pipe through' filter action in KMail.

BUG: 260638

Choosing collection icon works in kontact now, not only in
akonadiconsole.

The API changed and this was never ported.

BUG: 274681
(cherry picked from commit 7b6361c8)

CCBUG: 274681

To many people's surpise, including both me and volker, it was just a unused forward declaration
and some k3staticdeleter.

(cherry picked from commit 3ad3f45d)

    The remoteID .inbox was not recognized by the kmail kernel
    before. With this commit inbox mail filters will also be
    applied for inboxes with the remoteID .inbox

    Cherry-picked from: 4.6 : 1dbe3bf4

    The crash could be reproduced by clicking on knode, then
    going to config and disable it, then re-enable it, and clicking
    on it again ( basically making knode's ctor being called twice ).

    This KNGlobal stuff looks like a huge hack. So, KNGlobal creates
    a bunch of variables, then KNMainWidget gets ownership on them,
    but the getters are in KNGlobal. When ~KNMainWidget
    is called, it deletes those variables but KNGlobal will still
    hold pointers to them, and who ever calls the getters will
    obtain dangling pointers.

    Not sure why it was made that way, probably because KNGlobal
    uses external linkage, and somebody wanted to recreate stuff
    each time KNMainWidget gets recreated.

    Fixes kolab/issue4479
    cherry-picked from 30126b98

The "ContentMimeProperty" of the StandardActionManager::CreateCollection
action must be set.

We don't have a way to, through the UI, choose between event,
todo and journal folders though.
(cherry picked from commit b4217d31)

QMetaObject::invokeMethod() was failing.

Because true means that users should listen to this signal.

It's async now, we can't return bool.
Also, it always returned true.

It's async now.

Should be utf.

Should be utf.

- split freeBusyUrl() in two parts to remove the exec() call
  (was done for an Akonadi::ContactSearchJob) and add the
  slot to handle the job result();
- split processRetrieveQueue() in two parts to accomodate
  the previous change.