Previously, the user had to navigate to the context of a qml item in
order to edit its source code in Live Preview mode. This change tells
the client to update when new objects are created on server-side, and
makes the editing possible without having to manually trigger updates.

When a change is done to an element that cannot be changed due to
debugger/qdeclarative limitations, a warning is shown to the user in QML
JS Editor.

Reviewed-by: Olivier Goffart

This one should be called when a component is changed and components
using it need to be reloaded.

If an object is created at the same location of another old object,
It could be matched.

The crumble path shows the current context of the debugger/inspector.

Using more *::Constants::ICON_* where it makes sense and
wrapping the file names into QLatin1String where they were
missing.

The increased usage of the ICON constants needed a few more
cross plugin includes of *constants.h, here and there.
I think that it is OK, since the dependencies were alredy there
icon resource wise.

Two kinds of warnings are now shown: one for warning about the Live
Preview itself, as it is experimental, and another when user changes
id's of objects during runtime, as this is not supported at the moment.

More warnings will be added later for other unsupported changes.

A copy of the client debugging code is made in src/libs/qmljsdebugclient/
(this comes from the qt code from commit 65642dd343bf61)

So the qmljsinspector plugin does not require anymore Qt private headers.

Now, the items about to be selected must inherit from QGraphicsObject.
Also, coding style was cleaned up a bit.

To show the object string id's, the debug protocol is used to get them.
The problem is that the required methods in QDeclarativeContext(Data)
are not exposed, and it's too late to do it for 4.7.0. Hence this change
should be reverted in 4.8 when more efficient way of getting the id's
comes available.

The button is checkable and pressing it will stop/propagate changes to
the qml application being debugged.

Even if we should really care about all of them, the object that is the root
of all the graphical QML item is the usually last.

Also used 'int' instead of QDeclarativeDebugObjectReference for
the debug id in order not to use the private API from QMLJS

Such as anchors and font.

This required a little bit of refactoring.
The Delta::update should now be faster.

The root is enough because the rest of the tree will be added as the
root is added

When the document is reloaded by the server, we need to refresh
refresh what was the loaded document, and refresh the debugIds

We do not need this check anyway.

Else, the line numbers does not match anymore.

... with a little bit of refactoring.

But for some reason it does not seem to have an effect