Fixing idlestate if used with synchronous transport

If QtWebChannel is used with a synchronous transport it can
happen that the clients idle state is wrong because the clients
idle message is received before the idle state is set to
'false'.
This patch changes the order of setting the idle state and
broadcasting the property update message to avoid that problem.

Change-Id: I7762b5279febb99d3cb2e110ec9306596fc71e14
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Doc: Fix example documentation and paths

To fix issues related to example documentation and to follow Qt
convention, do the following changes:
    - Rename examples/qwebchannel to examples/webchannel
    - Move example-specific documentation to correct location(s)
    - Include generic 'Running the Example' instructions
    - Add the module name to example title, fix links

This ensures that example docs are built and the example manifest
file generated correctly.

Change-Id: I284e0b13db95a6738d72258735018b59156cc7da
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Remove unused #include statement

Change-Id: Ic51555b34823354092a5a4e8583c51d50a1aded8
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Doc: Enabled linking to qtdoc.

-added 'qtdoc' to the depends variables in
qtwebchannel.qdocconf file

Task-number: QTBUG-40756
Change-Id: Ida3e1aa1237bcd91f0280d1969c2361f4ee70405
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Remove the extra semi-colons

qwebchannel.h:60:101: error: extra ‘;’ [-Wpedantic]

Change-Id: I7623b68ace59431266ca6a48bfa23bc306363e7e
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Fixing property update for wrapped objects

Returned QObject pointer got wrapped correctly but
a wrong QJsonObject was given to initializePropertyUpdates()
method.

Change-Id: I157b862ba2a90e87c295beb3c02fff932aac83c6
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>