On black toolbars, the new icon doesn't look very well.
Now the toolbar icon has again a transparent "B" for better style on toolbars.
Does not affect the mac client.
Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>
- redefined the green color
- created new toolbar icons
- updated the assets-attribution.txt
Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>