Better display for dark favicons in the dark theme

[sabi0]

Dakr favicons (e.g. GitHub's one) are poorly visible when using dark theme. They should be inversed or highlighted in some other way.

Here is an example how they did it in Opera:
https://blogs.opera.com/desktop/2017/06/opera-47-beta/

[Croydon]

Does someone know a JavaScript library which can do the entire image manipulation?

I won't have time to write something on my own for likely a long time.

Integrating something existing should be fairly easy.

A library should somehow calculate the brightness of the entire icon, then decide if the colors needs to get inversed. Or something along these lines.

[Croydon]

This will finally land in the 0.13.0 release that I'm planning for the next few days

I might improve it in later releases further, see #224

[Croydon]

Closing.

Fixed by e901efc, dda4587, 7f8d4d3

Thanks @mmktomato!