Change IsSonic to properly use weapon Damage

Normally IsSonic=yes weapons only use AmbientDamage to damage everything in path of the sonic beam. I propose that those weapons should be changed to allow use of Damage as well, without hampering the AmbientDamage functionality. Damage would be dealt when the warhead is normally detonated.

This would allow use of the IsSonic=yes beam graphical effect more flexibly without being restricted to AmbientDamage way of dealing damage to targets along the beam's path. Non-zero Damage would also allow use of Warhead's AnimList as well.