Draw tracks in order to avoid wrong z-Indices
Draw tracks in order to avoid wrong z-Indices

Previously all 90 degree angles were drawn after all straight track segemnts
had already been drawn. Since drawing order in SVGs determines z-Indices
(which objects are behind/in front of others), this caused some wrong over-
lapping issues. This has been fixed by changing the drawing order, so that all
components of each color are drawn immediately after each other. Only then
drawing for the next color begins.

wolfib/sequenceTubeMap,wolfib/sequenceTubeMap