A Simutrans Prettification Project + Open GL dev

[_Hajo_]

Straight motion and this sort of curve,
https://en.wikipedia.org/wiki/Projectile_motion

Test have shown I need to add some more options for the initial direction of the particles. I'll post examples once I have that done. Also attaching a particle generator to a factory building has turned out more complicated than expected. I'll need some more time for that too.

[_Hajo_]

Now with extra sparkles! And attached to a factory. But map rotation screws it. I'll have to fix that before a release ... also need to make the particle size configurable, it's hard coded at the moment.

[_Hajo_]

Clouds make some pretty fat particles. Some day I'll try to animate the shower in the rainmaker too.