QIconLoader: don't inherit QObject
QIconLoader: don't inherit QObject

QIconLoader did not use the services from QObject and the
Q_OBJECT macro was missing, too, so external code couldn't
have used it in a qobject_cast or inherits(), either.

Port of commit
https://qt.gitorious.org/qt/qtbase/commits/7c6a4276f0330238d3d9438dc58a528c6cd4c80a

luis-pereira/libqtxdg,luis-pereira/libqtxdg,DrTobe/libqtxdg,lxde/libqtxdg,DrTobe/libqtxdg,DrTobe/libqtxdg,libqtxdg/libqtxdg,libqtxdg/libqtxdg,lxde/libqtxdg