Add delay on render to render flames

[Palats]

From Mazmot on Factorio forum:

Having an option to delay capturing will make nicer look & feel for furnaces.

In CLI version, this mod try to capture as soon as the save file loaded.
But stone/steel/electric furnaces don't start to firing at that timing.
So, the generated map looks weird because no flame on furnaces.
https://imgur.com/sRvYM3r

I modified a bit for myself: mazmot-is@df54564

Overall, it would indeed be nice to have better visual. I would like to keep the ability to also render without delay - it is more predictable and so on. A flag to set the delay could do the trick - though I wonder what the default should be between:

• No delay by default, predictable, but worse visuals
• Delay by default, better render, but a bit surprising (esp. if that's several seconds of extra delay).

I'll need to try things out a bit.