timetree + panel layout revisions

[rlskoeser]

design

• Propose logic for zoom levels based on the labels on the leaves on desktop and mobile  #35
• Propose a grid / logic for how much space elements take on a page on desktop, tablet, and mobile  #29
• design spacing for century containers #68

dev

• make it easier to configure forces used to layout leaves in the timetree #61
• label layout — break leaf labels into multiline #70
• As a user, I want to see tree branches as part of the timetree so I can more easily understand and read the visualization as a tree and see how the leaves connect. #71
• revise spacing and labels for century containers #72
• adjust network so leaves on same branch in the same century can spread further apart #87
• As a user on a smaller screen, I want to zoom in on the timetree so that I can view and interact with the content more easily. #69
• revise leaf shapes #177 (iceboxed)

[rlskoeser]

we've moved #177 and everything else here is complete; closing