Fix the qHash(quint64) overload

The body doesn't make sense as the if condition is always true
(we even have static asserts checking that sizeof(int) == 4).

Removing the if allows us to mark the function as constexpr.

Change-Id: Iddeb042a6164d4afe6c827c10177596424d770eb
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Make qHash(long) constexpr

By removing the if and switching to a ternary operator.

Change-Id: I754c312ef06cb1e029de8e6cc562de8b12c88fc4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Make qHash(QChar) constexpr

The signature needs a small change -- from qHash(QChar, uint) to
qHash(const QChar, uint). The reason is that we need to select
the const (and constexpr) overload of QChar::unicode in the body.

Apart from this, it shouldn't have any effect on user code.

Change-Id: I38f4f66a715111c7472e3d7def75a6cff7030919
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Add QCommandLineParser::showVersion(), similar to showHelp().

Change-Id: I1782c226ee8c457a68eb9ae9948a2a6a700d7a52
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>