Fix condition for warning
[cppcheck] Fix redundant variable initialization
[cppcheck] Remove unused audio::muteAmbianceTrack
Remove unused Ambiance::muteTrack
Remove Ambiance::Track::MUTED

Was never set.
Remove Ambiance::Track::REVERB

Was never used.
Remove audio::aalAmbianceFlag

Was not used.
Remove leftover member function declaration
audio: Add function to query reverb support
Disable EAX checkbox if reverb is not supported
Such MSVC performance warning, much serious