Slow and somewhat gradual switch between multiple colors (ie for holiday lighting)

[rlithgow1]

@calinatl , @mbishop has a holiday lighting app...

[Release] Holiday Lighting

It's cool to use colored lights for holiday displays. I just got RGBWW lights for my porch, and set out to configure them for holidays. Surprisingly, there are relatively few apps that allow scheduling different color palettes for different holidays. I found one lighting app which had a "holiday" mode, but it only allowed selecting a single set of colors; it would need to be manually changed for each holiday. So I wrote one. This app performs two related functions with a set of RGB lights: …