Mention Qt::ToolButtonFollowStyle in QToolBar/QMainWindow documentation

Improve the existing docu for Qt::ToolButtonFollowStyle in QToolButton
and show the same text in all other widgets that have toolButtonStyle property
(QToolBar and QMainWindow).

Change-Id: I26ff0ed332f8bd10b542a4111c6ae48a963d5667
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Port qdoc to QCommandLineParser

This will simplify future maintenance of qdoc, adding options being
much easier with QCommandLineParser.

As always, this revealed a number of undocumented options:
-log-progress, debug, -autolink-errors.

Compared generated docs with and without the patch, looked fine,
except that order differs (the qt_qhash_seed thing doesn't work)

Based on initial patch by Laszlo Papp.

Change-Id: I3c851135f2fd573d622d2ed456a11cee34e06054
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Martin Smith <martin.smith@digia.com>