Add setting to reduce space between dots

[Dylancyclone]

With the new setting that changes the shape of the dots into squares, I would love to see a feature that allows the user to reduce the space between the dots, so one could make a contiguous matrix clock, similar to this example, but without the borders between dots:

[thehale]

@DeDandeMan do you want to try tackling this one? The implementation would be almost identical to your work on roundness.

This would be implemented as a Spacing setting which ultimately modifies the margin style property of each dot.