Add proper choice of nearby sequences, rather than just the two nearest neighbors of the current one

[mvglasow]

Right now, when working on a stretch of road with a large number of sequences, systematically cycling through all of them is difficult. Jump to blue/jump to red offer only the nearest two sequences from the current one, and often you end up cycling through the same subset of sequences while never getting to others.

Instead of (or maybe in addition to) the jump to red/jump to blue buttons, I would suggest adding a dropdown list of all nearby sequences. Each list item would have the standard description, such as:

2020-02-02 by fakestevec