hides overloaded virtual function
Fix member signatures of deriving classes to its super classes.
Removes the unused idGameBustOutWindow::Activate() and the
useless idMarkerWindow::GetWinVarByName().
variable set but not used
Removes some CollisionModel code under _DEBUG which was probably a
leftover, since it was completely useless (its done later anyways).
The unused WriteLossless() was using libjpeg internals found in
jpegint.h. This header is available with libjpeg8, but not shipped
by most distros. Disable the relevant code - no functional
changes.