SVGOverlay: created staticMoveToAndSelectNode
webglapp: two consecutive treenodes with a defined radius will be shown as a cylinder
having as radius that of the child node.
Treeodes with a defined radius but without a radius in the parent or child
will be shown as spheres.
And these spheres and cylinders are shift+clickable to jump to the node in the canvas.

Additionally, the spheres are now icospheres with subdivision 2, with reused geometry throughout.
Cylinders also reuse geometry.
webglapp: use less memory, no need for orig_coord object or skeleton_id in every mesh.
Also reuse the pixel space vectors when possible--less multiplications.