changing shot momentum

[Betelgeuse]

We where talking on irc and came up with something we would like to do.

We would like to change the velocity of a shot in flight.

Couple things we would need is an <onFire> event so we could know when to start checking the shot and access to the shots (maybe as a global list of shots in the event)

There are many things that can be done with this. Like flight paths and alternative tracking weapons.