PRINCE: showLogo() - allow to skip logo animation or quit game during it
PRINCE: Allow to skip intro animation with LMB
PRINCE: Allow RTL engine feature
PRINCE: Add loading during startup and syncSoundSettings features
PRINCE: canSaveGameStateCurrently() - check conditions when you can't save the game state
PRINCE: canLoadGameStateCurrently() - to check if loading is allowed

Also block saving during dialogbox and inventory drawing
PRINCE: playSample() - split to sound and speech types to correct volume settings