[gurps] VehicleML: new files uploaded

[Onno Meyer]

* Replaced the old TOC by a chronological listing in front and an 
  alphabetical index in back. Other indices (by TL, by background,
  etc.) are equally possible. 
* Found out how to get the ammo type lists, in princple (doing 
  more than just the type is merely work). Getting references 
  right is still a challenge. 
* Added more weaponry, including a trebuchet and a water cannon.

Onno