ZVISION: Fix ZorkRaw stream decoder return true instead of real flag.
ZVISION: Don't use unneeded function.
ZVISION: Replace ZorkRaw audio parameters table by fully implemented with 16bit flag.
ZVISION: Implement engine-wide method for selecting new audio ID.
ZVISION: StateValue must be signed.
ZVISION: ActionAdd must handle negative vallues.
ZVISION: Implement ActionKill.
ZVISION: Implement ActionStop.
ZVISION: Implement MusicNode and move ActionMusic to work with it.
ZVISION: Add zgi_mx directory for files search