Make ambient light spots fade in and out

[Alzter]

SuperTux version: 0.6.0 Alpha 3
System information: Windows 10

I feel like the ambient light spots created by things like explosions, fireballs, and enemies should fade in and out instead of appearing suddenly.

[tobbi]

nice idea! Maybe we'll get to tackling it for 0.6.1

[HybridDog]

I think realistic explosions must not have fading lights and appear only for a very short time.
In SuperTux, the explosion cloud appears for several milliseconds, so maybe the cloud corresponds to remaining fire and smoke, which fades out; the explosion should not fade in.

[Rusty-Box]

I think this is something we should actually think about doing as it indeed looks pretty weird and clunky.