Modifier Logger to allow None as notification data

Ignore-this: 63adddbfe936feedd211c902b738b9df

darcs-hash:20091009165906-1e3d8-7c9255693ac31cdd5638a48d0fbefc18df771c59
Fixed SilenceableWaveFile to not ignore pause_time argument

Ignore-this: bf9590e4e28b1d316d7c0da8c307d9

darcs-hash:20091010120456-1e3d8-a257172a42c186c760697f19b20015538e2de81b