Add a Mainpage.dox for the GluonPlayer library too.
Add a Mainpage.dox for the GluonPlayer library too.

KDE/gluon,pranavrc/example-gluon,KDE/gluon,pranavrc/example-gluon,pranavrc/example-gluon,KDE/gluon,KDE/gluon,pranavrc/example-gluon