Test Plan: Build

Reviewers: dvratil, davidedmundson

Reviewed By: dvratil, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D12113

Summary:
Changing resolution of the 'Unified output' makes it move around which
then triggers QMLScreen::qmlOutputMoved() which tries to snap and re-align
all the outputs. This leads to the KScreen Outputs being positioned next
to each other in the final KScreen Config that is uploaded to KDED,
instead of on top of each other, virtually breaking the 'Unify outputs'
feature.

Test Plan:
Click 'Unify outputs' and change resolution of the unified screen. Click apply.
Resolution changes on both screens and they are now are correctly repositioned
to be in clone mode.

Reviewers: sebas

Reviewed By: sebas

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D8390

Outputs appearing at runtime weren't correctly positioned, since they
initially may be disabled, and are then enabled by the kded module
loading a known config. Disabled outputs don't have a position, and we
weren't updating it when enabling the output.

We can't simply listen to the output's posChanged signal since this
leads to complex round-trip loops with async calls.

BUG:366362

CCBUG: 341005

BUG: 339951
FIXED-IN: 5.3.0

This makes an output left of another output stay snapped to the right output
when it's resolution is changed.

This was there for a while and worked correctly after one of the adjacent
outputs was moved manually, which caused the docking to be re-evaluated.

BUG: 320012
FIXED-IN: 5.2.2

This also includes a few changes to use new Qt 5 connect API and C++11

It is quite verbose as it was using some intrinsic API of QGraphicsView that
is obviously not available anymore.
It seems to work to some extent now, but it would be really good if there
was some testing since I'm unsure about how to test it.

CCMAIL: Dan Vrátil <dan.vratil@gmail.com>

This makes it very easy to restore pre-unified state of outputs.