DisableDropSound misconception.

[GlenCFL]

Filtration treats the DisableDropSound rule as a boolean, when in fact it's the only rule in the game that doesn't take any value whatsoever. Any text that follows the keyword is simply ignored, with a boolean value actually being very misleading and resulting in unexpected behavior in-game.

This should eventually be clarified within the program.

[ben-wallis]

Fixed with #114