Annotation features requests

[patrickphillips98]

I have some ideas for some helpful annotation features.

Annotation at the voxel level that penetrates through several slices (like the annotation at the supervoxel level does). Or if can make it an option whether you want you annotation to penetrate several slices or just on that slice.

Fill option for annotation so you could draw a circle in voxels/supervoxels e.g. around a cell and then click somewhere in the middle and fill it all with one colour.

Thank you!