Undo icon white residue in dark theme

[yfdyh000]

No description provided.

[Mazzibig]

Try to fix icon

[yfdyh000]

@Mazzibig Thank you, it looks a little better, I would consider merging it.
I look forward to an automatic contrast and transparent icon, similar style.

[yfdyh000]

• Thanks to СерJант on https://addons.mozilla.org/firefox/addon/tab-utilities-fixed/reviews/786435.
• I use the https://tinypng.com/ to compress it, looks no differences. If you find differences, please let me rollback it.
• The icon was no significant difference (pure white) for dark theme compared to the default theme icons, but I guess it could be a complex compatibility issues for other themes, so I close it for now.

[yfdyh000]

I appreciate this icon, but encountered some technical problems for adapting it to the earlier versions. I don't want to abandon them, although this decision is not immutable.

[yfdyh000]

I have tried to limit its size using the max-width and max-height for Fx28 & Fx43 and earlier, but it always has some problems, such as too large, too small or scaling glitch on toolbar.

Fx44 and later seems to be working well, because https://bugzilla.mozilla.org/show_bug.cgi?id=1184651, but I don't know its condition for Win7 and Mac.

Welcome any patches, but I hope that it works well for Fx28~latest versions, including small icon mode on/off.

p.s. 64x64 of the icon (cropped):