VERSION 0.116.1268: renderer update, planning tutorial videos

Last week I analyzed a strange behaviour regarding the calculation of the alpha channel on low-density areas. This affected flames with non-black-backgrounds. This has been fixed now. There are other improvements regarding the consistency of renders between JWildfire and JWildfireSwan.

Also, I'm writing now the storybook for a series of introduction/tutorial videos for Swan.

And, there is some really cool new variation mady by Whittaker Courtney , which he sent me this week: "flame_bulb". Thanks, Whittaker!

Complete changelog:
VERSION 0.116.1268 (24.08.2025):
- flame-renderer: fixed a serious bug in the calculation of the alpha-channel (SWAN-136)
- flame-renderer: made the tonemapping more consistent between JWildfire and JWildfireSwan
- flame-renderer: made the tonemapping more consistent between different quality- and resolution-settings (experimental)
- flame-renderer: made the tonemapping more consistent between different oversampling-settings
- fixed a bug in the "post_circlecrop"-variation (SWAN-135)
- fixed a problem in the "japanese_maple_leaf"-variation (SWAN-125)
- main-editor: quick-preivew: use sampling-density from the currently selected
quality-profile
- application-settings: added settings "max. quick render quality" and "max. quick render size"
to limit the duration of the genration of a quick preview
- main.editor: added shortcuts for "add blank flame", "random flame" and "render image"
- new "flame_bulb"-varition by Whittaker Courtney