Remove mentioning of QML_CONSOLE_EXTENDED

The QML_CONSOLE_EXTENDED environment variable is gone since Qt 5.0.
Additional metadata is now available through standard means, e.g.

QT_MESSAGE_PATTERN=%{file}:%{line} %{message}

logs file, line information also for JS console statements.

Change-Id: Ie7fc2c35dd6b0f529aa8a151185f3894bec52e18
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Improved QUrl breaking information

Add a warning about the fact that QUrl has massively changed between Qt4
and Qt 5 as well as setPath new behavior

Task-number: QTBUG-27728
Change-Id: I9798eb4f06e42987a7c08d530467a31c14e47065
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>