VstBuffer should track segments

[osresearch]

The VstBuffer class should track segments, rather than individual points. This might make the sort algorithm simpler and maps well to the line() override.

[jacobjoaquin]

There are at least 4 different scenarios that should be considered for the VstBuffer, as this directly impacts optimizing the sort:

• Single point
  • Not implemented, but would be just a single visible point on screen.
• Line segment
  • Has a start and end point.
• Open multi-line segment
  • Has a differing start and endpoint with multiple line segments in between.
• Closed multi-line segment
  • Unlike open multi-line segments, any point in the shape should be considered when calculating distance against current transit point.
  • This is not accounted for in the current sort algorithm.