Violin/Box Responsiveness Improvements

[Daniel Marsh-Patrick]

• If the box width and/or height becomes less than its stroke width (x 2), then don't render it
• If the box height becomes less than the size of the mean circle then don't render the mean circle (like we have done with the box width already)
• Prevent the height/width of the mean getting too large at higher viewport sizes.

Others TBD

[Daniel Marsh-Patrick]

#30: Amended radius to not show if the size is larger than the box height. Resolves #30.

→ <<cset b47a3d9b486c>>