optimizing vertex creation order

[yakra]

Carving this out of #242 into its own issue.

With Waypoints stored contiguously, graph point setup iterating via system->route (benchmarked slower when WaypointQuadtree::graph_points was written although the method changed quite a bit ) rather than via quadtree may become faster.
Low impact, though. Low priority.
Potentially higher impact: Vertices created in this order may yield a more favorable compressed edge order, leading to better memory locality when writing files.

• unordered_set may jumble up the order and negate the benefit.
• forward_list should do better though, retaining the order of the edges creation.
• No-build should perform in between -- I expect allocation should go low->high, though it won't be perfect.
  None of the jumbling of unordered_set, but addresses of deleted temporary edges may be re-used for new edges.
• In any case, hi_priority & lo_priority vertex separation will jumble up compressed edge order a bit, but whatchagonnado.

3*2 ways to do it:

• Iterate by:
  • quadtree node, as done now
  • sys->rte->pts
  • rg->rte->pts
• No-build vs. eliminating extraneous visibility checks & branching thusly:

  else for (Waypoint *w : points)
   {	// singleton waypoints
  	if (!w->colocated)
  	{	if (!w->route->system->active_or_preview()) continue;
  		w->ap_coloc.push_back(w);
  		goto lo_priority;
  	}
  	// skip if not at front of colocation list
  	if (w != w->colocated->front()) continue;
  	// skip if this point is occupied by only waypoints in devel systems
  	if ([=](){for (Waypoint* p : *w->colocated) if (p->route->system->active_or_preview()) return 0; return 1;}()) continue;
  	// store a colocated list with any devel system entries removed
  	for (Waypoint *p : *(w->colocated))
  	 if (p->route->system->active_or_preview())
  	 w->ap_coloc.push_back(p);
  	// determine vertex name simplification priority
  	if (	w->ap_coloc.size() != 2
  	 || w->ap_coloc.front()->route->abbrev.size()
  	 || w->ap_coloc.back()->route->abbrev.size()
  	 )	lo_priority:
  		lo_priority_points.push_back(w);
  	else	hi_priority_points.push_back(w);
   }

What to observe:

• Speed
  • Setup / graph_points
  • Writing files
• RAM (with TMBitset::shrink_to_fit())
  • regions, systems, combined
  • vertices, edges, combined
  • more/less compact if ap_coloc.size() != 2 -> hi_priority?