Sounds that set the third argument of the playSound opcode to 1 (wherever they may be) will now block. The volume parameter of playSound is also now honored. Merge the Myst sound blocking code with this too.
svn-id: r52643
Merge the Riven sound file code with the main Riven resource code and remove the mainSoundFile parameter from Sound::playSound(). Reasoning: The sound id's do not collide with the sound id's in the main data files. The sound archives only exist because the original CD version had the ability to choose between low and high quality audio.
svn-id: r52631
