Teleportation sounds play twice, or no delay between teleportation

[John.d.h]

When teleporting, the unit instantly appears at the destination, followed by two sounds.  Presumably, one is for the beginning of the jump and one for the end, but it seems wrong because there is no delay and they are from the same set of sounds.  One solution would be to only play the sound once, and keep the rest of the behavior as it is.  Another solution would be to put a (preferably xml-defined) gap between disappearing and reappearing.  Splitting the sounds list into departure and arrival sounds would also be nice.

Easily demonstrated with this unit:
https://github.com/johndh/Project-Red/tree/master/project_red/techs/project_red/factions/magic/units/silver_mage