ImageFX fireworks hook

Written by Arend-Paul Spijkerman in 1998/1999

The fireworks hook tried to simulate the effects of a
fireworks burst.
By drawing pixels or brushes onto the image.

It does this by calculating gravity forces and other influences
on a number of particles.

Most of the influences can be set by using sliders
in the numerous menus.
Also Arexx can be used to make a complete fireworks animation.