basic implementation of marker-based style

[averrin]

We can configure marker styles like corner, dot, underline and etc....

[paulpflug]

a nice idea :smile:, maybe we should indeed make a option to toggle different makers.

• [x] solid background
• [ ] bottom border
• [ ] upper right corner

etc. I will have to think it through first

regarding the pr: the marker isn't cleaned up on color change, so there will be many markers when I cycle through colors.

[averrin]

Yeah, it was poorly tested.

[paulpflug]

Nice work :smile:

I will build on that..