This kills the funky GL logging stubs, which unnecessarily
complicates the build process (think future cmake).
As for logging GL calls: Use apitrace for that
https://github.com/apitrace/apitrace
hides overloaded virtual function
Fix member signatures of deriving classes to its super classes.
Removes the unused idGameBustOutWindow::Activate() and the
useless idMarkerWindow::GetWinVarByName().