Make candles flicker when movement near them

[Mooses2k]

Related: #168

• character moves nearby
• dungeon 'weather' event
• door opens or closes in room
• etc

"Enhanced Shader-Game World Interaction
Visual effect artists among you should find a lot of useful changes to the GPU-based particles. Those now come with support for attractors, collision, trails, sub-emitters and manual emission.

For effects that apply to the whole game world, like wind direction or wetness level, you can now share global values across materials."

Also, have some candles randomly just not as good

There should be at least two effects:

• candle flame visual itself should bend and flicker
• Light node location should randomly move locations based on the flicker too and lower light_energy level briefly with the flicker