BUG: 326095

Fixes resizeSplitters() being called N times.

Still doesn't fix the flickering completely.

When checking a calendar, all existing views were updated to
the sizes of the new agenda. It should be the other way around
the new one should get the size of existing ones.

mLeftSplitter and mRightSplitter are the only splitters that
aren't destroyed each time you check a calendar, so use that
as a reference.

CCBUG: 326095

Agendas weren't being created because it wasn't listening to
signals about them being checked or unchecked.

Still not happy about it, somethings weird with the default
sizes for the all day agenda, it appears too big at first.

CCBUG: 326095

Check mCustomColumnSetupUsed before executing code regarding
this feature.

CCBUG: 326095

FIXED-IN: 4.11.3
BUG: 326072

FIXED-IN: 4.11.3
BUG: 275575

description is html text so if we reduce text it will return just html code not text.

FIXED-IN: 4.11.3
BUG: 244113

FIXED-IN: 4.11.3
BUG: 326029

Adding to akonadi is async, and it can fail. Only send the answer
to the organizer after the incidence is stored in akonadi, and
only if it was successful.

Connect to a socket belonging to the current instance, instead of the
global one.

There was a missing signal.

BUG: 325428
FIXED-IN: 4.11.3

If we simply ignore the close event, Qt::WA_DeleteOnClose won't
have any effect and the dialog just gets hidden.

BUG: 325465

FIXED-IN: 4.11.3
BUG: 297157

FIXED-IN: 4.11.3
BUG: 310627

Keep ktextedit makes work.

FIXED-IN: 4.11.3
BUG: 324664